CITATION: Onespace Unlimited Inc. v. Plus Development Group Corp.,  
2022 ONSC 5317  
COURT FILE NO.: CV-15-527265  
DATE: 2022 09 19  
IN THE MATTER OF the Construction Act, RSO 1990, c. C.30, as amended  
B E T W E E N :  
) F. Miceli, for the plaintiff  
) C. Simcoe and M. Marrie, for the defendant  
) by counterclaim  
Plaintiff / Defendant by counterclaim )  
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) D. Rollo, D. Melamed, and V. Polutov,  
MCAP FINANCIAL CORPORATION, THE ) for the defendant / plaintiff by counterclaim,  
) Plus Development Group Corp.  
Defendants / Plaintiff by counterclaim )  
) HEARD: November 2-5, 9-10, 16-19, and  
) 24-25, 2021  
Associate Justice Todd Robinson  
ANALYSIS .........................................................................................................................4  
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Issue 1: Is it appropriate to dispense with the rule against hearsay for documents? ...5  
Issue 2: Are any of the unpaid services claimed by Onespace recoverable?.................5  
Unpaid F3 services ........................................................................................... 6  
Unpaid F4 services ........................................................................................... 7  
Extended duration........................................................................................... 11  
Issue 3: Did Plus breach the contract for non-payment? ............................................11  
Issue 4: Did Onespace breach the contract? ................................................................12  
Was Onespace’s suspension of services permitted by the contract? .............. 13  
What was the extent of Onespace’s contractual and professional duty to  
coordinate? ..................................................................................................... 13  
Did Onespace fail to meet the standard of care? ........................................... 24  
Were there deficiencies in Onespace’s designs? ............................................ 30  
Issue 5: Has Plus proved its alleged losses and damages? ..........................................33  
CONCLUSION ................................................................................................................33  
COSTS, INTEREST & REPORT ..................................................................................33  
This action involves a dispute arising from the construction of a 17-storey, high-rise  
condominium at 251-255 King Street East, Toronto, known as the King Plus Condos. The  
plaintiff, Onespace Unlimited Inc. (“Onespace”), was an architect engaged on the project. The  
defendant, Plus Development Group Corp. (“Plus”), is the owner/developer.  
The project dates back to 2008, when Plus’ principals, Walter Aronovitch and Ali  
Mohtashami, started a joint venture to develop the condominium. They engaged an initial design  
team to assist in advancing it. That team included TACT Architecture Inc. (“TACT”), an  
architectural firm engaged to prepare design drawings and assist Plus with the approvals process,  
and Jain & Associates Ltd. (“Jain”), a mechanical and electrical contractor. Plus also engaged The  
Moro Group (“TMG”) as the construction manager for the project.  
Onespace’s predecessor, Atkins Group Corporation, Architects (“Atkins”), was  
approached about acting as the project architect for construction. Atkins provided a fee proposal  
in August 2008 (revised in September) to Enirox Group (a company founded by Mr. Mohtashami).  
The fee proposal outlined various services that Atkins would provide. Enirox Group paid a retainer  
of $5,000 to Atkins in September 2008.  
There were delays getting the project to the construction phase, by which time Atkins had  
become Onespace. Onespace performed no services between Enirox paying the retainer and  
June 2011. During that period, design development had occurred and necessary project approvals  
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had been obtained. A pre-construction coordination meeting occurred on June 1, 2011, after which  
Ali Mohtashami confirmed that Onespace’s contract for the project would be with Plus.  
Onespace and Plus thereafter entered into a contract for Onespace to act as the construction  
architect for the project. The parties used an Ontario Association of Architects (OAA) Document  
600, 2008 standard form contract, with amendments. The contract includes two categories of  
chargeable services that are directly at issue in this action: services included as part of the fixed  
contract fee (referred to as F3 services) and additional services chargeable on an hourly basis  
(referred to as F4 services). Notably, several express exclusions from Atkins quote were replicated  
in Schedule A1 to the contract, as well as additional excluded items being added.  
Construction commenced sometime in 2012 and continued through 2015. There were a  
number of design changes during construction. By February 2015, Onespace had issued numerous  
invoices that remained unpaid by Plus. Onespace gave notice of its intention to suspended work  
for non-payment and, when payment was not made, did suspend all services under the contract.  
Plus takes the position that Onespace was directly responsible in delaying the job, overbilled, and  
invoiced for unapproved extras. Plus ultimately retained a new architect to complete the project.  
Onespace liened and commenced this action seeking to recover $155,910.10 in unpaid  
invoices. Plus has advanced a significant counterclaim against Onespace for delay and impact  
damages and design errors and omissions.  
Onespace is the only remaining lien claimant on the project. There were previously three  
other liens by contractors engaged by Plus, namely Roni Excavating Limited (“Roni”), an  
excavation contractor; Dircam Electric Limited (“Dircam”), an electrical contractor; and Delgant  
(Civil) Ltd.  
, a forming contractor. Roni’s lien was resolved by judgment granted by  
my predecessor in a separate stream of this reference. Dircam’s and Delgant’s liens were settled.  
As part of its claim, Plus seeks contribution and indemnity from Onespace for the settlement  
amount paid to Delgant.  
Fundamentally, the core dispute between Onespace and Plus is whether Onespace had any  
obligation on the project to coordinate the drawings of and communications between the various  
design consultants. Plus takes the position that Onespace did have that obligation, arguing that it  
was Onespace’s contractual and professional responsibility to perform the role of a managing and  
coordinating consultant. Plus alleges that there were errors, omissions, and conflicts in the  
consultant drawings resulting from Onespace’s failure to properly coordinate them and that  
inefficiencies led to delay and additional costs on the project. Onespace disputes that it assumed  
any managing consultant role, taking the position that Plus was itself responsible for coordinating  
the various consultants.  
[10] I find that Onespace was not a managing and coordinating consultant. Its obligation was  
limited to cooperating with other consultants in the coordination of drawings. I find that Plus has  
failed to prove that Onespace breached its contractual and professional responsibilities or  
otherwise breached the standard of care of a professional architect. I also find that Onespace has  
proven partial entitlement to its claim for unpaid services and that Plus breached the contract by  
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non-payment. Based on these determinations, I find that Onespace is entitled to a lien in the  
amount of $55,906.54, including HST, and judgment for the same amount, plus pre-judgment  
[11] Several issues are raised by the parties’ dispute, as follows:  
Is it appropriate to make a consent order dispensing with the rule against hearsay  
for documents?  
Are any of the unpaid services claimed by Onespace recoverable?  
Did Plus breach the contract for non-payment?  
Did Onespace breach the contract by suspending work for non-payment, failing to  
coordinate consultant drawings, or errors and omissions in its drawings? In  
Was Onespace’s suspension of services in accordance with the contract?  
To what extent did Onespace have any contractual or professional duty to  
coordinate the work of the design consultants?  
(iii) Did Onespace fail to meet the professional standard of care for an architect  
providing the services that Onespace was contracted to provide?  
If Onespace did breach the contract, has Plus proved its alleged losses and  
damages? In particular;  
Did the alleged delay events actually delay the project?  
Did Plus sustain any damages as a result of errors or omissions by  
(iii) Do the terms of the contract preclude or limit any liability to Plus?  
Is Onespace liable to reimburse Plus for any portion of its settlement with  
Delgant and, if so, was the quantum of that settlement reasonable?  
Did Plus cause or contribute to any of its own proven losses?  
Should any liability of Onespace be apportioned with others?  
[12] Section 87.3 of the Construction Act, RSO 1990, c C.30 operates such that the provisions  
of the act as they read on June 29, 2018 i.e., the provisions of the former Construction Lien Act  
(the “CLA) continue to apply to the improvement at issue and, thereby, the liens and lien actions  
arising from it. References in these reasons for judgment are accordingly to the CLA.  
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Issue 1: Is it appropriate to dispense with the rule against hearsay for documents?  
[13] The parties relied heavily on hearsay use of documents at trial, which was a concern that  
I raised with counsel. Many emails and other documents were put to witnesses that were not sent  
to or received by the witness. Other documents put to witnesses were authored by individuals who  
were not themselves called as witnesses at trial, such as representatives of TACT and Jain.  
[14] Prior to trial, the parties agreed that there were no objections to authenticity or admissibility  
of documents in the parties’ joint document book. They further agreed that all documents in the  
joint book would be admitted for the truth of their contents, falling under either the business  
records exception or the admissions exception to the rule against hearsay.  
[15] I am not convinced that either hearsay exception properly applies to many of the  
documents. Nevertheless, the parties consented to all documents in the joint document book being  
admitted for the truth of their contents. Plus’ counsel submitted at trial that the parties’ agreement  
was the basis upon which they proceeded to trial. Certainly it seems that witnesses were decided  
based on the agreement and legal arguments were made in reliance on it.  
[16] I have jurisdiction to dispense with application of the hearsay rule for this trial.  
Subsection 58(4) of the CLA provides me with all the jurisdiction, powers, and authority of a judge  
to try and completely dispose of this action. Subrule 55.01(1)(b) of the Rules of Civil Procedure,  
RRO 1990, Reg 194 (applicable by operation of s. 67(3) of the CLA) further provides me with  
discretion in this reference to dispense with any procedure ordinarily taken that I consider to be  
unnecessary or to adopt a procedure different from that ordinarily taken.  
[17] It would have been preferrable for the parties to discuss with me their intended hearsay use  
of documents at a hearing for trial directions well prior to trial. In my view, the parties were not  
entirely ad idem on the extent of agreed hearsay use. That has resulted in some muddy evidence  
at trial, with certain deemed admitted statements in emails at times conflicting with sworn  
testimony. However, the parties are sophisticated and represented by experienced counsel. They  
agreed to rely on documents contained in the joint document book for the truth of their contents.  
I find no basis to interfere in that arrangement for trial and find it appropriate to dispense with  
application of the rule against hearsay in respect of those documents. I deal with the extent and  
impact of the admission as and when necessary.  
Issue 2: Are any of the unpaid services claimed by Onespace recoverable?  
[18] No argument was advanced by Plus at trial that Onespace’s lien was not timely or that the  
services for which it liened were not lienable. I am satisfied that the lien was evidently preserved  
and perfected in time and an order for trial was obtained in Delgant’s lien action within two years  
of Onespace’s perfection. Since Delgant’s lien action is an action in which Onespace’s lien may  
be enforced, there was compliance with s. 37 of the CLA. Onespace’s lien is timely.  
[19] Quantum of Onespace’s lien and contract claim is seriously disputed by Plus. Onespace  
claims $155,950.10 in unpaid fees, comprised of $66,068 for F3 services and $89,842.10 for  
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F4 services. Onespace’s evidence in support of its claim was given by its president, Rod  
Rowbotham. In a brief affidavit, Mr. Rowbotham explains the difference between F3 services and  
F4 services and provides two charts with appended invoices. The first chart outlines the claimed  
unpaid F3 services. The second chart outlines the claimed unpaid F4 services, which  
Mr. Rowbotham describes as “deemed extras”.  
[20] Plus disputes Onespace’s billing, taking the position that the entire base contract price  
cannot have been billed when the project remained incomplete, that many charged extras were not  
approved or agreed, and that some of the services charged as extras by Onespace were included as  
base F3 services under the contract, so are not compensable above the base contract amounts.  
[21] As discussed below, I find that Onespace is contractually entitled to payment of  
$55,906.54. Onespace has failed to meet its evidentiary onuses for the remainder of its claim.  
a. Unpaid F3 services  
[22] Schedule A1 to the contract stipulates a fixed contract price for all F3 services of $252,000,  
plus HST. It apportions the F3 services fee as 65% for the construction document phase, 2% for  
bidding or negotiating phase, and 33% for construction phase contract administration.  
Notwithstanding that formal allocation, there is no dispute that Onespace’s fee was actually  
apportioned as $163,000 for construction documents services and $89,000 for contract  
administration services. Both parties’ records reflect that allocation.  
[23] The contract administration percentage is stated to be based on a fee of $5,000 per month  
for an 18 month schedule. That rate calculates to $90,000, which is slightly higher than the  
$89,000 allocated for contract administration. Nevertheless, Onespace did not invoice contract  
administration at $5,000 per month.  
[24] Onespace’s claim of $66,068 for F3 services is the total of 9 invoices rendered between  
May 2014 and January 2015. The invoices do not include consistent amounts or rates for contract  
administration. One invoice also includes a final billing for construction documents and four  
invoices include claimed reimbursable expenses for employee travel.  
[25] It is unclear from Onespace’s evidence how the contract administration billing amounts  
were calculated. Mr. Rowbotham testified that Onespace had taken the contract administration  
amount of $89,000 and divided it by the number of months over which construction was to have  
occurred and billed in equal amounts. Despite that evidence, though, the invoices do not reflect  
equal monthly billings, as already noted.  
[26] By the final invoice dated January 31, 2015, Onespace had billed the full base contract fee  
for F3 services of $252,000. Rod Rowbotham’s evidence at trial was that the 100% invoicing for  
contract administration did not reflect that all included F3 services had been fully completed.  
Rather, it reflects that the amount of services and tasks completed by Onespace outpaced the  
construction schedule, such that the budget for contract administration had been fully exhausted.  
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[27] I generally accept Mr. Rowbotham’s explanation for how Onespace invoiced F3 services,  
and GC 12.1 of the contract seems to support unequal monthly billing “in proportion to services  
performed within each phase of the service”. However, it is inconsistent with the contract for  
Onespace to have fully billed for contract administration services. Compensation for F3 services  
was expressly stated to be a fixed fee of $252,000. The required F3 services are identified in  
Schedule A to the contract, and they were evidently not fully completed at the time when Onespace  
suspended services. Onespace was accordingly not in a position to invoice the entire $252,000  
base fee. It had not yet completed all services included in that fee.  
[28] Onespace points out that the stated basis for the fee was $5,000 per month for an 18-month  
construction schedule, which was significantly surpassed. Onespace submits that I should consider  
the rate of $5,000 per month for the actual duration of contract administration. However, there is  
no evidence of any agreement between Onespace and Plus that contract administration services  
for any extended duration would be billable at the rate of $5,000 per month or as an F3 service.  
I was directed to no provision of the contract entitling Onespace to invoice additional contract  
administration for an extended duration as an F3 service. Onespace conceded in closing  
submissions that such charges are likely more properly viewed as F4 services.  
[29] There was no clear evidence on the extent of work performed by Onespace or the state of  
project completion when Onespace suspended its services. It is accordingly difficult to assess the  
extent to which F3 services were properly invoiced in accordance with the contract.  
[30] I am not satisfied that Onespace has met its onus of establishing that the unpaid F3 services  
were properly billable under the contract as F3 services. However, it is appropriate that I still  
consider Onespace’s claim for what amounts to an extended duration contract administration  
claim, but as an extra F4 service.  
b. Unpaid F4 services  
[31] Ali Mohtashami’s evidence is that, according to Plus’ records as of March 2015,  
$28,250.33 of the total extras claimed by Onespace were not disputed and had been paid. The  
balance of extras claimed by Onespace, totalling $89,842.10, are disputed as being unauthorized,  
unapproved, or improperly billing F3 services as F4 services.  
[32] Onespace has the evidentiary onus of proving its claimed extras, but tendered limited  
evidence to substantiate its claim for F4 services. The work for the $89,842.10 in claimed extras  
was predominantly performed by Mauro Franzoni, a former principal of Onespace, and Chris  
Payne, an architectural technologist employed by Onespace at the time. Mr. Franzoni was not  
called a witness at trial. Each of Rod Rowbotham and Chris Payne gave some evidence on extras,  
but it was general. Otherwise, Onespace relies on its unpaid invoices in and of themselves.  
[33] Some of Onespace’s extras invoices include a general description of the claimed extra.  
Some do not. Those that do not are typically supported by time dockets that include descriptions  
of the work performed and hours spent. Since the invoices were admitted for the truth of their  
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contents, I accept Onespace’s argument that the descriptions of work, record of hours spent, and  
supporting dockets may be taken as proving that the hours indicated were, in fact, spent on the  
identified tasks and that the tasks were performed as stated. Based on the agreed hearsay  
admission, I thereby accept that the services identified as “extra” were, in fact, extras.  
[34] However, in my view, the fact that statements in the invoices have been admitted for the  
truth of their contents does not fully assist Onespace. The admission does not extend to admitting  
that the extras were properly billable to Plus under the contract. That is a legal, not factual, issue.  
[35] Onespace is only entitled to recover extras in accordance with the contract. The contract  
provides chargeable hourly rates for F4 services, which are identified in Schedule A to the contract.  
Schedule A1 outlines the process for chargeable extras, as follows:  
Additional Work And Corresponding Hourly Rates  
For additional work as may be requested, the Client will be forwarded a Request for  
Extra Services Form requiring signature and agreement to fees based on hourly rates  
as outlined herein and specified disbursements before onespace unlimited inc. proceeds  
with the work. Invoices for additional services and changes of scope shall be billed  
upon completion of the additional scope of work.  
Additional work shall include but not be limited to the following:  
a) Site visits in excess of those quoted.  
b) Revision to drawings required by Client following prior approval.  
c) Work beyond the scope of this proposal  
d) Work of other Specialty Consultants.  
Additional work will be charged at the rates quoted above under F4 Services.  
[36] The process outlined in Schedule A1, as above, formally required signed authorization  
forms with prior agreement on fees and disbursements for all F4 services. Onespace concedes that  
work authorizations were not obtained for its claimed extras. Onespace instead argues that case  
law (including my own prior decision in an unrelated action) supports that knowingly allowing  
extra work to be performed may give rise to an implied promise to pay for it. I agree that is a  
correct statement of law.  
[37] Terms of a construction contract that require extra costs to be authorized in writing may be  
varied by the parties’ conduct. Where a party acquiesces in an extra being provided and, as a  
reasonable person, must have realized the extra work would involve extra expense, that party may  
be found to have made an implied promise to pay for it, irrespective of the strict contract terms:  
Reid v. Xiao, 2021 ONSC 7468 at paras. 31-32; Multitech Contracting 2000 Inc. v. GJ Investments  
Inc., 2021 ONSC 69 at para. 36.  
[38] Mr. Rowbotham’s affidavit discusses how Onespace would “typically” prepare an  
“Additional Services Authorization Form” and send it to Plus, but that it was “common practice”  
for Onespace to be asked to start immediately because a requested service was time sensitive. Ali  
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Mohtashami’s evidence is that there was no such common practice. Only a handful of additional  
services forms were tendered at trial, mostly unsigned.  
[39] Onespace emailed its additional services forms to Walter Aronovitch for signature, not to  
Ali Mohtashami. Mr. Aronovitch did not testify at trial. Evidence supports that he did not sign  
the additional services forms, but also that he did not dispute them.  
[40] One additional services authorization form dealt with attending additional coordination  
meetings. Evidence supports that Onespace was asked and expected to attend them, but neither  
Walter Aronovitch nor Ali Mohtashami signed the additional services authorization form sent by  
Onespace. Mr. Mohtashami testified during cross-examination that the additional services were  
neither approved nor rejected. He expressed his view that coordination meetings ought properly  
to be viewed as part of the F3 services, but also confirmed that Onespace was never told that they  
would not be compensated for the meetings. Onespace evidently viewed its attendance at the  
meetings as an extra, which is set out clearly in an email sent by Mr. Franzoni to Walter Aronovitch  
on April 1, 2014. That view was never corrected. Mr. Mohtashami also testified that he had told  
Mauro Franzoni that they could discuss whether it could be charged as an extra, but that the  
discussion did not happen.  
[41] Similarly, an additional services authorization form was tendered dealing with extended  
duration contract administration from July 2014 to June 2015. Mr. Mohtashami could not confirm  
if it was received or approved, glibly suggesting that Onespace’s counsel should ask Walter  
Aronovitch, who Plus did not call as a witness despite his likely alignment with Plus’ interests.  
[42] Although the evidentiary record on requested extras is less than ideal, I am satisfied that  
the totality of the evidence supports that the contractual requirement for written authorization of  
extras was not strictly adhered to by either party. I find that it was varied by the conduct of the  
parties to allow for extras that were not formally pre-approved in writing.  
[43] Since the formal extras term was varied, determining whether the claimed F4 services are  
properly recoverable extras requires Onespace to demonstrate three elements: (a) the base contract  
scope of work changed so fundamentally that the contract price no longer applies to the services  
and materials actually supplied, (b) there was an express or implied agreement for supply of  
services and materials claimed as extras, and (c) in the absence of agreement on a price for the  
extras, whether the value of extras has been proven on a quantum meruit basis: Osmi Homes Inc.  
v. Kumar, 2020 ONSC 2712 at para. 94.  
[44] In my view, Onespace has failed to prove that Plus was actually aware or reasonably ought  
to have been aware that the claimed extra services were being provided and acquiesced in them.  
Admission of Onespace’s invoices for the truth of their contents does not address Plus’ knowledge  
and acquiescence. Even taking that the work identified was performed and was an extra, most of  
the entries do not refer to any request or authorization by Plus.  
[45] No specific evidence was given on authorization and approval for most of the claimed  
unpaid F4 services. I do not accept Onespace’s argument that the evidence supports that Ali  
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Mohtashami commonly requested extra work and required that it proceed immediately. The  
evidence supports that some authorizations were sent and requested, but not consistently. As  
noted, only a handful of authorization forms are in evidence, significantly less than the number of  
extras claimed. Onespace did not tender specific evidence on Plus’ request for or agreement or  
acquiescence to the extras outlined in each of its extras invoices. Notably, Onespace did not  
cogently correlate emails and requested authorizations to its specific invoices.  
[46] I do not accept Onespace’s argument that Plus “obviously” had knowledge that Onespace  
was performing extra work and never requested or demanded that such work stop. I was directed  
to no evidence at trial supporting such a general finding nor did Onespace make any convincing  
argument for why all claimed extras should be painted with the same brush of having been agreed  
(expressly or impliedly) by Plus.  
[47] The best evidence tendered dealt with the request by TMG for Onespace to attend  
additional coordination meetings, which is the subject matter of one of the requested additional  
services authorization forms. There is evidence supporting that Plus was aware that Onespace was  
attending those meetings, but not that Ali Mohtashami or Walter Aronovitch agreed that those  
attendances were extras to the contract. There is frankly insufficient evidence on the extent of  
required coordination meetings to decide if the further meetings are properly viewed as extras.  
[48] I also give no effect to Onespace’s argument that Plus has not explicitly denied that the  
work constituted extras, but rather that Plus has only given evidence that it was not aware of what  
it was being billed for. Mr. Mohtashami’s largely unchallenged evidence is that he did not  
understand that much of the design work charged by Onespace as extras was actually extra  
services, which is why Plus did not approve the claims as F4 services.  
[49] Regardless, I am not prepared to infer agreement or acquiescence from any lack of a  
specific denial by Plus for each claimed extra. Onespace has the evidentiary burden to prove its  
claim, which includes proving that Plus knew or ought to have known that the work was being  
performed, knew or ought to have known that it was an extra, and either agreed to the work or  
acquiesced in it. Onespace opted to tender only general evidence on the fact of extras, opted to  
rely on a general argument about Plus’ express or implied agreement to them, and trusted that  
admitting the invoices for the truth of their contents would close any gap. It did not.  
[50] It is not the court’s role to sift through a shoebox of unorganized evidence to connect the  
dots. Onespace had the evidentiary obligation of tying together the extra, the express or implied  
agreement to the extra, and the agreed price for each claimed extra. In my view, Onespace has not  
done so, and specifically has failed to adequately address Plus’ express or implied agreement to  
specific extras.  
[51] Accordingly, even if I accept that the work was performed and constituted an extra,  
Onespace has not met its evidentiary onus on a balance of probabilities to prove express or implied  
agreement by Plus for supply of the claimed F4 services as extras. An extra is not legally  
recoverable without such agreement.  
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c. Extended duration  
[52] Notwithstanding my findings above, I am satisfied that Plus did agree to pay most of  
Onespace’s invoices totalling $66,068 for F3 services, dealing essentially with extra costs incurred  
by Onespace for the extended duration of its contract administration.  
[53] Rod Rowbotham gave evidence about a meeting with Ali Mohtashami and Walter  
Aronovitch at Onespace’s offices on January 14, 2015. He testified that they went over Onespace’s  
invoices and it was agreed that the 8 invoices from May to December 2014, totalling $55,906.54,  
were not disputed and would be paid. Mr. Rowbotham’s evidence and understanding is  
corroborated by a subsequent contemporaneous email dated January 23, 2015, in which  
Mr. Rowbotham followed up on payment as discussed and specifically listed the invoices and their  
totals. A further email to that effect was sent on February 6, 2015. No email correcting  
Mr. Rowbotham on payment of the invoices was sent in response to either email.  
Mr. Mohtashami’s testimony that there was no agreement is entirely uncorroborated by any  
contemporaneous emails or records.  
[54] There was no cogent evidence disputing Mr. Rowbotham’s account and, as noted, a  
complete lack of any contemporaneous clarification or denial sent in response to  
Mr. Rowbotham’s emails. I accordingly find that there was an agreement for Plus to pay 8 of the  
9 invoices totalling $55,906.54.  
Issue 3: Did Plus breach the contract for non-payment?  
[55] Plus’ position is that, to the extent that any monies were owing to Onespace, it is entitled  
to a set-off for its own claims and thereby was not in breach of the contract for non-payment.  
Onespace argues that the general conditions to the contract say otherwise.  
[56] Plus argues that a complete copy of the contract with definitions and general conditions  
was never provided to it. However, Ali Mohtashami did not give any evidence to that effect,  
including in reply to Rod Rowbotham’s responding affidavit evidence, which discussed and  
appended the general conditions. In any event, Plus does not dispute that I may consider the  
totality of the contract, including the definitions and general conditions. In my view, it would not  
have been credible for Plus to argue otherwise. The contract expressly refers to the general  
conditions and no cogent evidence was given that Ali Mohtashami was unaware of them or that  
they applied.  
[57] GC 12.2 provides that Plus is not entitled to make any deductions from amounts payable  
to Onespace on account of penalty, liquidated damages, or other sums withheld from payments to  
contractors, or on account of the cost of changes in the work other than those for which [Onespace]  
is proven to be legally responsible or has agreed to pay.” Onespace argues that this clause  
precludes any withholding. I disagree.  
[58] Contrary to Onespace’s position, GC 12.2 provides an exception in favour of Plus: when  
Onespace is proven to be legally responsible. The clause does not clearly state that Onespace must  
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be proven legally responsible prior to a deduction. However, that does not mean that Plus was  
entitled to withhold all payment without any notice of asserted set-off.  
[59] Mr. Rowbotham’s evidence at trial was that no one on behalf of Plus raised any failure to  
coordinate with him at any point prior to litigation commencing. Ali Mohtashami gave evidence  
that he raised complaints about lack of coordination with Mauro Franzoni, but that evidence is  
entirely uncorroborated by any contemporaneous emails. I found it to be a bit too convenient.  
Regardless, there is no evidence supporting that any formal notice of default by Onespace was  
ever given by Plus nor notice of an intention by Plus to withhold payment due to Onespace’s  
breaches of contract prior to its suspension of services. The contract does not expressly require  
such notice, but in my view notice was nevertheless required as a matter of good faith contract  
[60] Had Plus given formal notice of its intention to set-off against amounts owing to Onespace  
for Plus’ increased costs of changes required by Onespace’s alleged breaches of contract, it may  
have been able to rely on the exception in GC 12.2 to justify non-payment. Since Plus did not, in  
my view, non-payment constituted a breach of contract.  
[61] I note that s. 17 of the CLA limits Onespace’s lien to the least amount owed by Plus in  
relation to the project. That includes considering all debts, claims or damages owing to Plus by  
Onespace, whether or not related to the improvement. Accordingly, despite my finding that  
Onespace is owed $55,906.54 and that Plus breached the contract by failing to make payment,  
whether or not Onespace is entitled to a lien and judgment still turns on the extent to which Plus  
has proven its own set-off claim and counterclaim.  
Issue 4: Did Onespace breach the contract?  
[62] Plus has advanced a significant counterclaim for losses and damages, which are  
particularized in the Scott Schedule exchanged between the parties in the litigation. A number of  
the listed items were withdrawn prior to or at trial.  
[63] Plus alleges that Onespace caused damages and losses by breaching the contract in three  
ways: (i) by invalidly suspending its services, (ii) by failing to discharge its contractual and  
professional duties to coordinate the consultant drawings, and (iii) by errors and omissions in its  
own drawings. These are alleged to have caused significant delays at the ground floor level and  
at the mechanical penthouse at the roof level as well as causing Plus to suffer additional losses  
outlined in its Scott Schedule.  
[64] I reject Plus’ arguments that Onespace breached the contract. I find that Onespace’s  
suspension of services was not in breach of the contract. I further find that Onespace’s  
coordination obligation was limited to cooperating in coordinating drawings with other consultants  
who were affected by Onespace’s designs or whose drawings affected Onespace, but it did not  
extend to managing the coordination of all consultant drawings. I also find that Onespace met the  
professional standard of care for an architect on this project and that Plus has failed to prove any  
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causation between alleged errors and omissions in Onespace’s drawings and conduct and Plus’  
claimed damages.  
a. Was Onespace’s suspension of services permitted by the contract?  
[65] Section A14 in Schedule A1 to the contract permits Onespace to cease work if invoices  
remain unpaid after 45 days and Onespace has given seven days’ written notice that it will stop  
rendering services.  
[66] Notice that Onespace would be suspending services was given by email to Ali Mohtashami  
and Walter Aronovitch on February 11, 2015. That email, sent by Rod Rowbotham, expressly  
provided seven days’ notice of the intent to suspend services if payment was not made. Subsequent  
notice that services were being suspended for non-payment was given by a further email sent on  
February 18, 2015, which expressly provided that services would resume upon receipt of payment.  
That was confirmed in a subsequent email dated February 24, 2015.  
[67] Although I have not accepted that the separately billed F4 services are recoverable, work  
was only suspended for non-payment of “base contract services”, as clearly set out in  
Mr. Rowbotham’s emails, namely the first eight invoices comprising Onespace’s F3 services  
claim. I have found that Plus agreed to pay the specific invoices noted by Mr. Rowbotham in his  
email dated January 23, 2015, and failed to pay them.  
[68] No particular form of written notice is specified in the contract. Mr. Mohtashami evidently  
received the emails, since he responded to them. I am satisfied that the email notices were proper  
notices under the contract and that Onespace complied with the terms of the contract in suspending  
services for non-payment. I thereby find that Onespace did not breach the contract by suspending  
its services.  
b. What was the extent of Onespace’s contractual and professional duty to coordinate?  
[69] Plus argues that Onespace breached the contract by failing to coordinate the preparation of  
drawings on the project in accordance with its contractual obligations, which Plus argues led to  
delays and additional costs. In particular, Plus’ position is that Onespace was specifically engaged  
to coordinate all drawings between and among the consultants, including communications between  
them. Plus also argues that, regardless of the express coordination obligations in the contract,  
Onespace also had an independent professional obligation to manage and coordinate drawings.  
[70] I agree with Plus’ submission that the emails and evidence before me support that no one  
(including Plus) was actually in control of coordinating the various design consultants’ drawings.  
That, however, does not itself lead inevitably to a finding that Onespace ought to have been in  
control and failed to do so. I also need not delve to far into Onespace’s argument that Plus, through  
Ali Mohtashami, had assumed the role of coordinating the consultants. Deciding who was  
responsible for managing coordination of consultants is not necessary to decide whether it was  
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[71] I find that Onespace was contractually and professionally required to cooperate in  
coordinating drawings with other consultants, but that Onespace was not required to assume a  
managing coordination role.  
i. Did Onespace have a contractual obligation to coordinate drawings?  
[72] The dispute over the extent of Onespace’s express coordination obligation stems from  
different interpretations of the standard form contract language in the agreement portion of the  
contract, the coordinating obligation in Schedule A to the contract, and exclusion language drafted  
in the typed Schedule A1 to the contract, as follows:  
Article A9.2 of the contract stipulates that Onespace is responsible for coordinating  
the services of specific consultants engaged by Plus, namely structural, mechanical,  
electrical, site servicing, shoring, and historical;  
In Schedule A, ss. 27-34 identify specific coordination functions for Onespace as  
F3 services. Onespace’s obligation was to “coordinate the services of the following  
consultants with those of the architect”, listing structural engineer, mechanical  
engineer, and electrical engineer; and  
In Schedule A1, a list of various items are identified under the heading, “Items Not  
Included In Fee”. One of them is “Coordination of Consultants work.”  
[73] The distinction between the parties’ positions is subtle, but significant. Onespace’s  
position is that, reading the stated contract obligations together with the Schedule A1 exclusion,  
its obligation was limited to coordinating its own drawings with other consultants. Onespace  
submits that it had no obligation to manage coordination and communication of other consultants,  
including ensuring that all drawings were coordinated.  
[74] Plus argues that the Schedule A1 exclusion for “Coordination of Consultants work” is just  
that: Onespace was not required to coordinate the work of other consultants and, accordingly, had  
no liability for any of their work as it would have if they were its own subconsultants. However,  
Plus argues that the exclusion does not apply to managing the coordination of drawings, including  
coordinating necessary communications between the consultants.  
[75] I have applied the following principles in my interpretation of the contract:  
Contractual interpretation is an exercise in which the principles of contractual  
interpretation are applied to the words of the written contract, considered in light of  
the factual matrix: Sattva Capital Corp. v. Creston Moly Corp., 2014 SCC 53 at  
para. 50;  
The overriding concern in contract interpretation is to determine the objective intent  
of the parties and the scope of their understanding, which requires that the contract  
be read as a whole, giving the words used their ordinary and grammatical meaning,  
- 15 -  
consistent with the surrounding circumstances known to the parties at the time of  
forming the contract: Sattva, supra at paras. 47 and 49;  
It is unnecessary to consider any extrinsic evidence when the document is clear and  
unambiguous on its face. To interpret a plainly worded document in accordance  
with the true contractual intent of the parties is not difficult, if it is presumed that  
the parties intended the legal consequences of their words: Eli Lilly & Co. v.  
Novopharm Ltd., [1998] 2 SCR 129 (SCC) at paras. 55-56 (cited in Dunn v. Chubb  
Insurance Company of Canada, 2009 ONCA 538 at para. 33); and  
Interpreting a written contractual provision must always be grounded in the text  
and read in light of the entire contract. Surrounding circumstances must never be  
allowed to overwhelm the words of that agreement, and cannot be used by the court  
to deviate from the text such that the court effectively creates a new agreement:  
Sattva, supra at paras. 57;  
A contractual provision is ambiguous if it is reasonably susceptible of more than  
one meaning: Dunn, supra at para. 34;  
Literal meaning must be given to the language of the contract unless it would result  
in absurdity. Words of ordinary use in a contract must be construed in their ordinary  
and natural sense: Grossi Consulting Services Limited v. Premier Salons Ltd., 2014  
ONSC 5028 at para. 13, citing Gerald Fridman, The Law of Contract in Canada,  
6th ed (Toronto: Carswell, 2011) at 436-437; and  
Where handwritten or typed amendments to a contract conflict with the standard  
form terms and conditions, unless that conflict can be resolved by the usual  
techniques, the handwritten or typed terms should take priority over the inconsistent  
standard terms. Preference should be given to the terms that the parties have clearly  
chosen for themselves and therefore constitute the best evidence of their intentions:  
John D. McCamus, The Law of Contracts, 3rd ed (Toronto: Irwin Law, 2020) at  
pp. 829-830.  
[76] As noted, Onespace does not dispute that the contract required it to coordinate its drawings  
with the other consultants as part of its F3 services. In the standard form Schedule A to the  
contract, ss. 27-34 provide that Onespace is obliged to coordinate the “services” of the structural,  
mechanical, and electrical engineers “with those of the architect” as F3 services. Onespace’s  
argues that “with” is significant language. It is argued to confirm that the coordination obligation  
is limited to ensuring that Onespace was coordinating withother consultants, but not that  
Onespace was responsible for coordination ofother consultants. It had no contractual obligation  
to exercise any control or take lead in coordinating others.  
[77] I generally agree with Onespace. My own interpretation of the contract supports  
Onespace’s position that its coordination obligation did end there, at least as an F3 service.  
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[78] Plus points to the definition of “work” in the standard definitions for the OAA Document  
600, 2008, which is defined to mean “the total construction and related services required by the  
construction contract documents.” Plus argues that definition supports its position that Onespace  
was only excluded from a prime consultant role, but not from coordinating drawings and  
[79] In my view, the definition of “work” cannot be applied to the exclusion in Schedule A1.  
It would lead to an absurdity in interpreting the meaning of “coordination of consultants work.”  
The term “work” in the OAA Document 600, 2008 is used to refer to the actual construction. For  
example, s. 76 in Schedule A provides that Onespace is required to attend site meetings and, where  
appropriate, to “review the progress of the work.” It is also found it the definition of “construction  
cost” in the context of calculating the architect’s and consultant’s fees based on the costs “to  
complete the work”. It is also found in the definition of “place of the work”, which refers to “the  
designated site or location of the work identified in the construction contract documents.”  
[80] Since the definition of “work” cannot be reconciled with the non-standard form written  
exclusion for “coordination of consultants work”, I have considered both the word and the phrase  
in their ordinary and natural sense. In that light, “work” in reference to consultants reasonably  
means the work that those consultants are required to perform, although what the consultants were  
required to do is described throughout the contract as “services”. I find no meaningful distinction  
between “work” and “services” in this context.  
[81] All relevant consultants were required to produce drawings as part of their supply of  
services. Coordinating all consultants’ drawings would thereby seem to fall squarely within an  
exclusion for coordinating consultants’ work.  
[82] My difficulty with Plus’ proposed interpretation of “work” is that it distinguishes the scope  
of the consultants’ work between drawings and other services despite there being no such language  
in the exclusion. Notably, ss. 27-34 in Schedule A to the contract refer to coordinating “services”  
not “drawings”, yet Plus is not arguing that Onespace had any coordination obligation for  
consultant services beyond drawings and related communications.  
[83] Plus points to Ali Mohtashami’s testimony about discussions with Mauro Franzoni and  
Walter Aronovitch about the need to rely on Mr. Franzoni’s expertise, including consultant  
coordination. Mr. Mohtashami’s evidence was that it would not make sense for him to have  
negotiated F3 services that included coordination and then have the coordination of work excluded.  
[84] Despite that evidence, though, in my view, accepting Plus’ interpretation is contrary to the  
principles discussed above, notably that a contract must be read as a whole, giving all terms  
meaning, and further that any terms separately written and agreed by the parties should be given  
priority over standard form terms.  
[85] Plus further points to the definition of “consultant coordination” in the standard definitions  
for the OAA Document 600 as supporting its position. That term is defined to consist of three  
elements: (i) managing the communications between consultants and with the client, (ii) providing  
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direction as necessary to give effect to any design decisions taken, and (iii) reviewing the product  
of the work to assist in identifying conflicts and to monitor compliance with directions.  
[86] However, “consultant coordination” is not a term used in any relevant part of Schedule A.  
As a defined term, the definition has meaning when that term is used in the contract, as is the case  
with the other defined terms. A definition is not itself a standalone source of obligation in a  
contract. I was not directed to any part of the contract using the defined term, so I am unable to  
find that the definition has any bearing on Onespace’s contractual coordination obligations.  
[87] Plus also argues that I should apply the principle of contra proferentem, which was  
discussed by my predecessor, Master Albert, in Pegah Construction Ltd. v. Panterra Mansions  
Joint Venture Corp., 2013 ONSC 3226 at paras. 64-69. The principle operates to interpret  
ambiguity in the wording of a written contract against the interests of the person who drafted the  
contract. Contra proferentem is, however, an interpretive principle of last resort to be applied only  
when other rules of contract construction are inadequate. It is also generally reserved for situations  
where the party drafting the contract dictates the terms with no meaningful opportunity to the non-  
drafting party negotiate or modify the contract wording, such as a car rental contract.  
[88] Pegah involved a dispute arising from a condominium construction project involving  
renovation of an existing building and construction of a 34-unit high-rise condominium addition.  
It required interpretation of a contract negotiated between the owner/developer and the contractor.  
Master Albert found that the principals of the two parties who negotiated and executed the contract  
were “both sophisticated and experienced individuals who have worked in the construction and  
development industry for many years.” The principal of the contractor was Ali Mohtashami.  
Master Albert held that it was not necessary to resort to contra proferentem based on her finding  
that both negotiating individuals were sophisticated and experienced in construction: Pegah, supra  
at paras. 68-69.  
[89] In my view, the situation is the same here. There is no evidence suggesting any inequality  
of bargaining power between Onespace and Plus. To the contrary, the evidence before me supports  
that Mauro Franzoni for Onespace and Ali Mohtashami for Plus were both sophisticated and  
experienced in construction. Mr. Franzoni is a licensed architect. Mr. Mohtashami is a trained  
civil engineer with a Master of Business Administration who has worked in the construction and  
development industry for years.  
[90] I am satisfied and find that Onespace did not have any contractual obligation to manage  
coordination of consultant communications and drawings as part of its base contract F3 services.  
Nevertheless, reading the contract as a whole, I do not agree with Onespace that the coordination  
function was excluded from the contract entirely. That is not what the contract says.  
[91] Much of the focus at trial was on whether including “coordination of consultants work” in  
Schedule A1 excluded coordination from the contract. However, properly interpreted, Schedule  
A1 does not purport to exclude the coordination function from the contract. Rather, it is part of a  
list entitled, “Items Not Included In Fee”. The only “fee” discussed in the contract is Onespace’s  
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fixed fee for F3 services. Put another way, the listed items are not included in Onespace’s  
F3 services fee, but that is not necessarily the same as excluding them from the contract entirely.  
[92] Rod Rowbotham stated his view that the list of exclusions applies not only to F3 services,  
but also to F4 services. However, Mr. Rowbotham did not negotiate the contract and his view is  
inconsistent with the list itself. For example, the list has an exclusion for revisions as contemplated  
in item 26 in Schedule A, which is listed as an F4 service. It also excludes site visits in excess of  
36, all disbursements, and HST. To interpret the list as excluding these items from the contract  
would be inconsistent with Onespace’s own extras billing, which includes revisions to drawings,  
site visits, disbursements, and HST. I find that, read in the context of the contract as a whole, the  
“Items Not Included in the Fee” are only exclusions from the fixed fee for F3 services.  
[93] It follows that the effect of Schedule A1 was to exclude “coordination of consultants work”  
from Onespace’s F3 services, but not the contract. Article A9 provides an express obligation on  
Onespace to coordinate certain consultants. I agree with Plus that the exclusion in Schedule A1  
does not supplant article A9. In my view, the exclusion only renders the article A9 coordination  
obligation an F4 service.  
[94] I am nevertheless satisfied that the evidence supports there was never any actual  
requirement for Onespace to coordinate the consultants identified in article A9. I accept  
Onespace’s argument that the article reflects only a listing of those consultants retained directly  
by Plus. I find that the parties, by their conduct, varied the formal term such that Onespace had  
no coordination obligation beyond the F3 service identified in Schedule A, namely to cooperate  
with other consultants in coordination.  
[95] Despite listing structural, mechanical, electrical, site servicing, shoring, and historical  
consultants as requiring Onespace’s coordination in article A9, the evidence does not support that  
Plus expected or that Onespace had agreed to perform any such coordination. I say this for four  
[96] First, the evidence supports that Plus did not expect or require Onespace to coordinate the  
services of the shoring or heritage consultants. Ali Mohtashami confirmed during his cross-  
examination that Onespace had nothing to do with the shoring design. The design and construction  
work overseen by the shoring consultant. His evidence was only that Onespace would have to  
coordinate its drawings to existing site conditions. Mr. Mohtashami’s cross-examination evidence  
further supports that Onespace had no involvement and was not expected to be involved in  
coordinating the heritage consultant.  
[97] Second, contrary to Plus’ argument at trial, the evidence does not support a mutual  
intention or agreement that Onespace would be responsible for coordinating all consultant  
drawings and communications.  
[98] Ali Mohtashami’s evidence is that, in the course of various meetings with Mauro Franzoni,  
both Mr. Mohtashami and Walter Aronovitch expressed that Plus needed Onespace’s expertise,  
including coordination of the consultants. While Mr. Franzoni was not called as a witness by  
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Onespace to refute that evidence, neither was Mr. Aronovitch to corroborate it. Mr. Mohtashami’s  
evidence is further uncorroborated by any contemporaneous evidence. There are no emails,  
memoranda, or any other document supporting his evidence.  
[99] Plus argues that Mr. Mohtashami’s evidence is uncontested. That is technically true.  
However, I can accept Mr. Mohtashami’s evidence that he discussed the need for Onespace to  
coordinate the consultants, but still find that Plus has not proved that Onespace agreed to perform  
that coordination function.  
[100] I note that Mr. Mohtashami’s evidence does not go so far as to say that Mauro Franzoni  
agreed that Onespace would coordinate the other consultants. Mr. Mohtashami’s evidence at  
paras. 15-16 of his affidavit sworn February 3, 2020 speaks to his understanding of what he and  
Walter Aronovitch relayed to Mauro Franzoni. He says he was “satisfied” that Mr. Franzoni  
“understood our needs and his role”, but does not state why or how he was satisfied. His evidence  
falls short of stating that Mr. Franzoni acknowledged Plus’ need for Onespace to act in a managing  
coordination role and agreed to have Onespace assume that role.  
[101] Plus argues that I should draw an adverse inference from Onespace’s failure to call Mauro  
Franzoni. It is a factor. However, it does not override that Ali Mohtashami’s evidence was  
consistently that Mr. Franzoni was made aware of Plus’ expectation for coordination, not that  
Mr. Franzoni expressly agreed to undertake coordination. That is a distinction with difference  
given the exclusion language in Schedule A1 of the signed contract, which was not one of the  
exclusions in Atkins original quote. The Atkins quote stated only that Atkins would “Coordinate  
our work with that of the other consulting team members.”  
[102] In my view, without clear evidence or corroboration of an agreement by Mauro Franzoni  
for Onespace to take on a managing coordinator role, the relevance of Ali Mohtashami’s evidence  
on his own expressed desire or expectation has limited evidentiary value.  
[103] Third, there is a lack of any evidence supporting that Onespace had any actual authority  
over the other design consultants, which is further inconsistent with Mr. Mohtashami’s evidence  
and Plus’ position. None of the other consultants were subconsultants to Onespace. Each of them  
contracted directly with Plus.  
[104] Similarly, no evidence supports that the other consultants were directed to follow Onespace  
as coordinating lead or had any contractual obligation to do so. To the contrary, the evidence  
supports that the other consultants were all paid by Plus, that they were consistently reporting to  
Ali Mohtashami, that they followed directions from Mr. Mohtashami on design changes for non-  
architectural items, and that Mr. Mohtashami did not consistently discuss those design changes  
with Onespace. Many were not raised or discussed with Onespace at all.  
[105] Fourth, the evidence does not support that Plus genuinely viewed Onespace as being  
responsible for coordination during the scope of the project. For example, emails and evidence  
from Ali Mohtashami’s cross-examination support that Mr. Mohtashami took it upon himself to  
directly coordinate a significant design change to move the main electrical room from the roof  
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level to the P1 level. There is no evidence that Mr. Mohtashami had any discussions with  
Onespace about the change or expected Onespace to be involved. Notably, there is no evidence  
of any communication with Onespace about coordinating the change and no evidence supporting  
that Plus had stepped in because Onespace was failing to do so.  
[106] Similar evidence was before me on value engineering work being undertaken in late 2013,  
which was being managed by Ali Mohtashami. Mr. Mohtashami requested that Onespace  
coordinate Jain’s revisions with architectural, and provided an additional work form to complete  
that work as an F4 service. In my view, that is inconsistent with Onespace already being expected  
to conduct the coordination function as part of its scope of work.  
[107] Given Plus’ position that Onespace was always required to coordinate the design  
consultants, one would expect to see emails or other documentary supporting that Plus had  
demanded Onespace to “do its job” during the course of the project. There is none. Although Ali  
Mohtashami gave evidence that he complained to Mauro Franzoni, there is no corroboration of  
that. In my view, the emails to which I was directed do not clearly indicate any expectation that  
Onespace was to provide overall drawing and communication coordination, rather than Onespace  
simply coordinating its own drawings with other consultants affected by them or whose work may  
impact architectural design.  
[108] Rod Rowbotham testified that Plus never raised lack of coordination until after this  
litigation had started. That would include during meetings and discussions over non-payment, in  
which Mr. Rowbotham was directly communicating with Ali Mohtashami and Walter Aronovitch.  
[109] The foregoing factual evidence supports a finding that the parties did not genuinely intend  
for Onespace to perform a managing coordination function. However, it also supports Onespace’s  
argument that, even if there was a coordination obligation under the contract, the parties agreed by  
their conduct to vary that term.  
[110] In my view, the conduct of the parties in the course of the project is consistent with  
Onespace having no responsibility for coordinating the drawings of and communications between  
the consultants as either an F3 service or an F4 service. I find accordingly.  
ii. Did Onespace have a professional duty to coordinate drawings?  
[111] Plus submits that Onespace was obliged to discharge its duties and obligations under the  
contract in accordance with professional standards. Plus argues that included a professional  
obligation on Onespace to monitor and manage the coordination of drawings between the  
[112] Two experts were tendered dealing with the professional standards applicable to architects,  
particularly with respect to coordination and architectural design of a project. Plus tendered expert  
evidence from Martin Gerskup. Onespace tendered expert evidence from Vincent Alcaide. Both  
are experienced architects. Mr. Gerskup was qualified as an expert on the standard of care for  
architects in condominium construction and Mr. Alcaide was qualified as an expert on the standard  
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of care for architects in development, design, construction, and contract administration processes  
of buildings, including high rise condominium buildings.  
[113] Overall, I prefer and give greater weight to the opinion of Vincent Alcaide on the relevant  
standard of care. Martin Gerskup, while quite experienced and having had experience in smaller  
condominium projects, admittedly has no experience as an architect in high rise condominium  
design or construction. Conversely, Mr. Alcaide is very experienced in it. Mr. Alcaide also had  
access to substantial project documents and correspondence, whereas Mr. Gerskup formed his  
opinion with reference to only limited project documents and only three pieces of correspondence.  
In my view, the more limited review of project documents impacted Mr. Gerskup’s ability to  
inform his opinion with reference to both the parties’ actual dealings and the dealings between the  
[114] In addition, Mr. Gerskup’s opinion that Onespace was a “managing and coordinating  
consultant” is premised on a contractual interpretation that Onespace was responsible for  
coordinating the structural, mechanical, electrical, site servicing, shoring, and historical  
consultants. As already discussed, I have not accepted that interpretation of the contract, which  
impacts the weight I give to Mr. Gerskup’s opinion.  
[115] Regardless of the contract, Mr. Gerskup’s opinion is that Onespace had a professional  
obligation as an architect to coordinate drawings of other consultants. Mr. Gerskup’s opinion, as  
expressed during cross-examination, is that an architect cannot contract out of the coordination  
responsibilities contemplated by the OAA Document 600, 2008. That appears premised on the  
view stated in his report that, in his experience, “all design decisions are ultimately the  
responsibility of the architect.” No cogent foundation for these opinions was established in his  
report or at trial.  
[116] Vincent Alcaide’s oral testimony often exceeded the scope of his expertise, discussing  
topics such as typical developer obligations and engaging in factual interpretations of the  
relationship between TMG, Plus, and Onespace. While I have given reduced weight to those  
aspects of his testimony, I nevertheless found his opinion on the extent of an architect’s  
professional responsibilities for coordination to be helpful and well within his expertise.  
[117] Mr. Alcaide’s opinion is that design decisions made by an architect in a high-rise  
condominium development are typically limited to general design of the building and appearance,  
Building Code related matters, and technical performance of architectural design elements such as  
building cladding, roofing, and interior components for the building. Other aspects of the project  
are controlled by the developer, including the scope of services of other consultants the developer  
has hired. Not only is Mr. Alcaide’s opinion supported by his experience, but it is also consistent  
with Plus’ conduct on this project.  
[118] Mr. Gerskup opines that a coordination obligation is consistent with the professional  
standards outlined in the Architects Act, RSO 1990, c. A.26, and its regulation, RRO 1990, Reg 27.  
In his report, Mr. Gerskup specifically discusses the following:  
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s. 22 of the Architects Act, which requires that architectural services provided by a  
corporation must be supervised by a member of the Ontario Association of  
Architects “to the same standards of professional conduct and competence in  
respect of such practice of architecture as if the member personally engaged in the  
practice of architecture”; and  
ss. 47, 49, and 50 of Reg 27, which outline various requirements for standard of  
practice dealing with file and record maintenance, staffing and supervision  
requirements, and scope of general review services.  
[119] Mr. Gerskup acknowledged during his cross-examination that the Architects Act does not  
contain any references to design coordination standards. In my view, none of the provisions of the  
Architects Act and its regulation cited by Mr. Gerskup mandate any obligation on Onespace to  
coordinate other consultants as part of its scope of work.  
[120] For example, Mr. Gerskup cites and relies on s. 50 of Reg 27. Subsection 50(1) discusses  
coordination of general review, which Mr. Gerskup acknowledged during cross-examination  
would not apply to the design phase. That subsection expressly distinguishes between an architect  
“specifically engaged” to coordinate general review and one that is not. Under s. 50(1)(vi), an  
architect that is not engaged to coordinate the general review of engineers and reports of inspection  
and testing companies is only required to cooperate in it. I have found that Onespace was not  
specifically engaged for such coordination.  
[121] Mr. Gerskup’s opinion also relies on the Canadian Handbook of Practice for Architects  
(CHOP) and OAA practice tips on coordination of consultants. Plus argues that the standard of  
care can be influenced by the rules set by a self-regulating body: Livent Inc. v. Deloitte & Touche,  
2016 ONCA 11 at para. 199; Hodgkinson v. Simms, [1994] 3 SCR 377 at para. 52. I agree.  
However, I accept the opinion of Vincent Alcaide that CHOP and the OAA practice tips are not  
rules, but rather are non-regulatory and advisory in nature. In my view, they have no bearing on  
Onespace’s obligations or the applicable standard of care in the particular relationship between  
Onespace and Plus.  
[122] With respect to CHOP, although Mr. Gerskup and Mr. Alcaide agree that CHOP is properly  
considered as a guideline for how architects should be managing and coordinating consultants,  
they differ on whether it should be considered in informing the standard of care. I agree with  
Mr. Alcaide’s view that CHOP provides guidance for architects retained to provide coordination  
services, but does not itself require the architect to be responsible for coordination of consultants.  
[123] Significantly, CHOP includes an express disclaimer that provides, in part, as follows  
(emphasis added):  
The Handbook describes procedures for general practice only and is neither exhaustive  
nor complete. Based on specific facts or circumstances, the application of these  
procedures may vary, such as variances from province to province. The Handbook  
outlines recommended practices; however, these recommendations are not to be  
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interpreted as a standard of practice or a standard of care in the provision of  
professional services.  
[124] During Mr. Gerskup’s cross-examination, Onespace also effectively demonstrated that the  
examples of coordination outlined in CHOP were not applicable to the relationship between  
Onespace and Plus, namely establishing budgets, design criteria, and time schedules; arranging  
meetings; routing all communications; and setting standard formats for documentation. The type  
of coordination apparently contemplated by CHOP is much broader than the coordination role that  
Plus argues that Onespace was obliged to perform.  
[125] CHOP does provide that, where an architect and engineers are each engaged separately by  
the client (such as Plus), then “the architect must ensure that the architect’s services and fees for  
coordination and management of the consultants are clearly understood and agreed to.” However,  
I am not convinced that such a statement supports that the default standard of professional  
responsibility on an architect is to manage all coordination unless the parties expressly agree  
[126] Two of the OAA practice tips tendered by Plus at trial are from March 2021, well after  
Onespace’s suspension of services. Relevant professional standards are those prevailing at the  
time the work was done, not what may be known or accepted at a later time: Ontario (Ministry of  
Labour) v. Nor Eng Construction & Engineering Inc., 2008 ONCJ 296 at para. 101.  
[127] The 2012 version of OAA Practice Tip PT.27 on consultant coordination was not put to  
any witness. In any event, it expressly sets out that an architect’s or engineer’s coordination  
responsibility arises “[w]here an owner retains either an architect or engineer as the coordinator of  
all consultants”. In my view, the practice tip only applies to architects who have been specifically  
contracted to coordinate other consultants. While that is described as “a basic part of the services”  
in standard form agreements, I have found that the contract between Onespace and Plus did not  
include a requirement to coordinate all other consultants, or even to coordinate all other  
consultant’s drawings or communication between them.  
[128] Vincent Alcaide’s opinion is that that Onespace’s coordination services were limited to  
cooperating with other consultants to ensure coordination and proper development of drawings.  
Mr. Alcaide does not excuse Onespace from any coordination obligation. He expressly stated  
during cross-examination that, in his view, Onespace still had a professional and ethical  
responsibility to work with the consultant team. However, his view is that Onespace discharged  
that duty and made all reasonable efforts to coordinate its work in the context of continuous design  
changes beyond its control.  
[129] I am satisfied and find that Onespace did not have any overriding professional  
responsibility or obligation beyond its contractual duties to manage coordination of all consultants’  
drawings. However, Onespace may still have breached the standard of care if it failed to cooperate  
with the other consultants in necessary coordination.  
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c. Did Onespace fail to meet the standard of care?  
[130] Plus damages are outlined in its Scott Schedule, which is comprised of 29 items. In its  
written and oral closing submissions, Plus confirmed that Scott Schedule item nos. 6, 7, 10, 13,  
16, 17, 20, 21, 22, 25, 26, and 27 were not being pursued. The balance of items fall into three  
categories: damages flowing from delay, damages flowing from lack of coordination, and  
damages flowing from design errors and omissions. I have considered whether Onespace met the  
standard of care with reference to those items.  
[131] On the totality of the evidence, I am satisfied and find that Onespace did meet the standard  
of care of a professional architect and thereby did not breach the contract.  
i. Relevant legal principles  
[132] In Ontario (Ministry of Labour) v. Nor Eng Construction & Engineering Inc., supra at  
para. 101, several principles applicable to the professional standard of care for architects and  
engineers were discussed, which are also applicable here. I summarize them as follows:  
architects and engineers owe a duty to exercise the skill, care and diligence  
reasonably expected of a person of ordinary competence, measured by the  
professional standard of the time;  
architects and engineers are not obliged to perform to the standards of the most  
competent and qualified members of the profession, unless they contract to do so;  
absent agreement to exercise a higher standard of care, all that is required of an  
architect or engineer is reasonable skill, care and diligence as judged generally by  
standards of competence in the profession in which they practice;  
the relevant professional standards are those prevailing at the time the work was  
done, and not what may be known or accepted at a later date; and  
provided the architect or engineer has exercised reasonable judgment, competence  
and diligence in doing the work, they will not be liable to the client for breach of  
contract or negligence even if the work proves unsatisfactory in some way.  
[133] Plus also raises Blair v. Gren Weis Architects and Associates, in which Seppi J. held that  
it was “plain and obvious” that an architect’s failure to respond to a specific concern raised about  
its design fell short of what a reasonably responsible architect should do. That failure was held to  
constitute a breach of the professional duty as an architect, which required that the architect  
respond to and rectify, whenever possible, the design deficiencies expressed by the client: Blair  
v. Gren Weis Architects and Associates, 2006 9961 (ON SC) at para. 56.  
[134] However, it is significant in assessing Onespace’s performance that the professional  
standard of care does not require perfection. A professional may make incorrect decisions or reach  
erroneous conclusions, but such errors in judgment are not necessarily negligent. What must be  
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assessed to determine if an error in judgment gives rise to liability is whether that judgment was  
exercised reasonably and on an informed basis: Trizec Equities Ltd. v. Ellis-Don Management  
Services Ltd., 1998 ABQB 1133 at para. 422.  
ii. Did Onespace delay the progress of construction?  
[135] In support of Onespace’s liability for delay, Plus relies on the opinions of its two experts,  
Martin Gerskup and Ron Fernandez.  
[136] Ron Fernandez was qualified as an expert in delay analysis and quantification of damages.  
He was engaged to assess if Delgant suffered any delay and, if so, the causes and length of delay  
and the extent of losses or damages suffered by Delgant. Mr. Fernandez’s opinion is that Delgant  
was delayed a total of 114 calendar days, in part because of design errors and omissions. He  
assessed delay in five “windows” for Delgant’s concrete forming work.  
[137] Martin Gerskup reviewed Ron Fernandez’s report and provided an opinion that Onespace’s  
failure to coordinate the consultants resulted in delays impacting Delgant in two of the windows:  
(i) the window from March 7, 2014 to July 7 2014, covering the commencement of the P1 slab  
work to completing the ground floor slab, and (ii) the window from November 26, 2014 to  
February 12, 2015, covering the commencement of the level 16 slab to completing the roof slab.  
[138] In support of Onespace’s position that it has no liability for delay, Onespace relies on the  
opinion of its expert, Alan Peter Halsall, a structural engineer. I qualified him as an expert in  
structural engineering and processes related to procurement, design and construction review for  
buildings, including high rise condominiums. However, I did not qualify him an expert in causes  
of delay in construction, since I was not satisfied that he had any particular expertise in that area.  
Ultimately, given my findings, Mr. Halsall’s opinion has proven to have very little bearing on  
deciding this case.  
[139] There is no real dispute that there were delays to construction in both of the two windows.  
However, Onespace’s liability for those delays is squarely in dispute. Plus claims contribution  
and indemnity towards its settlement with Delgant, which included claimed delay from both  
windows. Plus also claims damages for its own separate delay and impact losses.  
[140] As discussed below, I find that Onespace did not cause or contribute to either window of  
delay and that Plus has failed to meet its evidentiary onus of demonstrating other claimed delays.  
It follows that there was no breach of contract and, further, that Onespace has no liability for Plus’  
claimed delay-related losses. Those include Plus’ claim-over for its settlement with Delgant (Scott  
Schedule item no. 1), claimed amounts for carrying costs and costs from delayed occupancy (Scott  
Schedule item nos. 3-5), and claimed costs for additional bonding and accounting due to delay  
(Scott Schedule item nos. 28-29).  
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(1) P1 slab to ground floor slab  
[141] With respect to the P1 slab to ground floor slab window, evidence supports that Delgant  
identified a concern with insufficient spacing in the architectural and structural drawings to allow  
for necessary mechanical and electrical penetrations in the slab. The insufficient spacing resulted  
in congestion of mechanical and electrical conduits. Reinforcing steel had to be added and changes  
were required to the beam layout. The re-design, which included the reinforcing steel and changes  
to slab elevation, resulted in delays to Delgant’s forming work.  
[142] I am satisfied that the delay resulted, at least in part, from a lack of coordination. Martin  
Gerskup opines that there were no substantive changes in Jain’s mechanical and electrical  
drawings. The design simply did not fit within the architectural and structural designs. However,  
no evidence was tendered supporting that it was Onespace who, in fact, failed to coordinate with  
Jain or CH2M Hill (“CH2M”), the structural engineer. No witness was called from either of those  
consultants and none of Plus’ witnesses gave any specific evidence on what, if any, coordination  
occurred between Onespace, Jain, and CH2M on the conduit issue. Plus’ argument hinges on  
general inferences from other evidence.  
[143] In closing submissions, Plus’ counsel advanced an argument about necessary flow of  
information between Onespace, Jain, and CH2M to avoid conflicts in their drawings. Plus submits  
that Onespace would need to have known what mechanical and electrical openings were required,  
as well as their dimensions, in order to add them to the architectural drawings. Those drawings  
would then need to be sent to CH2M. CH2M would review them and design the structural  
elements accordingly. However, none of the experts gave evidence to that effect and none of the  
witnesses gave any evidence supporting that such a flow of information did not occur.  
[144] I do not find it appropriate to draw an inference that Onespace failed to take reasonable  
steps to coordinate simply because an expert has opined that Jain’s drawings did not change. I am  
also not prepared to infer that the absence of the openings on architectural drawings means that  
Onespace failed to confirm the mechanical and electrical needs of Jain. There is no evidence of  
[145] Article in Section 03200 of the project specifications outlines an obligation on TMG  
and affected trades to “[p]repare reinforcement shop drawings and bar lists taking into account all  
openings and recesses shown on the architectural, structural, mechanical and electrical drawings,  
and on the sleeving shop drawings.”  
[146] Onespace further points to TMG’s contract with Plus, which includes an obligation to  
coordinate consultants at GC 2.3.6. Specifically, that general condition states that TMG is to assist  
Plus “in selecting and retaining the professional services of any consultants, engineers or other  
specialists that may be required, and coordinate these services, without assuming any  
responsibility or liability of or for these consultants or their work.” GC 4.4 clarifies that Plus has  
directly engaged consultants and that those consultants are responsible for designing the project.  
However, that is not inconsistent with TMG having an overall coordination obligation.  
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[147] No representative of TMG was called as a witness. However, as already discussed, the  
parties’ agreement was that all documents were admitted for the truth of their contents.  
[148] Evidence tendered at trial also supports that CH2M repeatedly asked TMG for the drawings  
that showed necessary sleeves on each level for mechanical, electrical, and plumbing in  
December 2013, February 2014, and April 2014. Nothing was provided until May 1, 2014. While  
Martin Gerskup suggested that the lack of responses and poor coordination supports that Onespace  
was “missing in action”, in my view, it supports only that TMG was failing to discharge its own  
obligations under the project specifications and its contract.  
[149] Jain’s scope of work was confirmed in its own letter dated May 15, 2008 to include, “The  
design and preparation of mechanical/electrical working drawings on architectural backgrounds  
provided by the architect and coordination of the same with the construction manager and all  
applicable consultants” (emphasis added). I was directed to no evidence supporting that Jain  
discharged its obligation to coordinate its own working drawings. Evidence at trial did not address  
why Jain had not already identified that architectural and structural drawings did not allow for  
necessary mechanical and electrical penetrations prior to Delgant raising concerns.  
[150] Chris Payne testified that Onespace would not have determined where openings in the  
ground slab for conduits would go, but would review them if there was a large opening that was  
in conflict. His evidence was consistent with mechanical and electrical conduits being primarily  
coordinated between the mechanical and electrical consultant (Jain) and the structural consultant  
(CH2M). I was directed to no evidence on the size of the necessary penetrations supporting that  
they reasonably ought to have been reflected on architectural drawings. I am not prepared to infer  
that they ought to have been shown based solely on Delgant raising concerns about congestion and  
the fact that a re-design was ultimately required.  
[151] I am not satisfied that the totality of evidence supports a reasonable finding that any act or  
omission by Onespace resulted in the architectural and structural drawings failing to adequately  
show sufficiently large openings for the mechanical and electrical penetrations. In my view, Plus  
has not established on a balance of probabilities that Onespace failed to cooperate in coordinating  
drawings or had a deficiency in its own drawings falling below the standard of care. I accordingly  
find that Onespace did not cause or contribute to delay in the P1 slab to ground floor slab window.  
(2) Level 16 Slab to Roof Slab  
[152] With respect to the level 16 slab to roof slab window, Plus argues that Onespace failed to  
coordinate with Jain on the height of the mechanical room, which lead to delays when necessary  
mechanical equipment could not be accommodated in the designed space. In particular, Jain’s  
drawing M211 from June 2010 indicates a 9.5-ft height requirement that was not reflected in the  
architectural drawings. Onespace’s drawings showed only an 8-ft height.  
[153] Plus asks that I draw an inference that Onespace had access to drawing M211 and the  
information on Jain’s mechanical height requirements. However, Plus was unable to direct me to  
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any factual foundation for a proper inference that Onespace ought reasonably to have had that  
information. There is no evidence on whether Onespace was provided with drawing M211 or if it  
was available on the consultant ftp site. Onespace argues no evidence supports that had the  
drawing. There was also no evidence on other communications about Jain’s height requirements  
to which Onespace was privy or that were reasonably available to it. No witness from Jain was  
[154] In February 2011, prior to Onespace’s involvement, TACT circulated its building plans to  
all consultants at that time, including Jain, and requested that they review their respective  
disciplines and advise any conflict or design adjustments that may be required re. structural,  
mechanical, electrical or code.” Onespace demonstrated that TACT’s drawings do not include a  
10-ft mechanical penthouse. Evidence supports that an omission was not raised by Jain. Evidence  
also supports that Onespace was not advised of the height requirements by either TACT or Jain  
when Onespace became involved in June 2011.  
[155] During closing submissions, I asked counsel for submissions on a seeming discrepancy  
between the TACT drawings, the permit drawings, and Onespace’s design drawings. It appeared  
to me that, based on TACT’s design drawings as cross-referenced against the permit drawings,  
TACT may actually have allowed for up to a 9.8-ft mechanical enclosure, whereas Onespace’s  
designed only allowed for an 8-ft enclosure. However, neither party tendered any evidence on  
discrepancies in the mechanical enclosure between design drawings by TACT and Onespace. It is  
thereby unclear in the evidence whether Onespace did, in fact, reduce the size of the mechanical  
enclosure and, if so, why that may have occurred. However, in my view, having further considered  
the issue that I raised, nothing turns on it.  
[156] Plusprimary argument is that Onespace ought itself to have inquired about Jain’s height  
requirements sooner and identified the conflict. However, there is no evidence supporting a  
finding that Onespace ought reasonably to have been aware that the mechanical penthouse needed  
to be higher prior to Jain identifying the design conflict in March 2014. Jain had access to  
Onespace’s drawings, which depict an 8-ft mechanical enclosure. Jain reasonably knew the  
dimensions of the required mechanical and electrical equipment. There had been dozens of  
coordination meetings prior to March 2014. Nevertheless, Jain did not raise the insufficient height  
issue at any meeting or in any correspondence until March 2014.  
[157] Absent evidence supporting that Onespace had any notice that the 8-ft mechanical  
penthouse would be insufficient, I find it was reasonable for Onespace to expect that Jain would  
advise of any conflict with its own mechanical design requirements.  
[158] The evidence also supports that there were ongoing delays in Jain providing updated  
mechanical drawings throughout the project, including after identifying the conflict in the  
mechanical penthouse height. The inference that Plus invites me to draw against Onespace relies  
on a hypothetical assumption that Jain would have provided the information if asked, which seems  
contrary to the evidence of Jain’s non-attendance at meetings and delayed or lack of timely  
responses to communications.  
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[159] In an email dated March 11, 2014, Dinesh Jain of Jain acknowledged that Jain should  
have noticed this earlier. Based on the parties agreement, that statement is admitted for the truth  
of its contents. I thereby have an admission that Jain ought to have been aware of the conflict  
sooner, supporting that the failure to identify it sooner was Jain’s error. That is coupled with a  
lack of evidence supporting any reasonable inference that Onespace could or ought itself to have  
been aware of the conflict between architectural design and the mechanical equipment height any  
earlier than when Jain raised it.  
(3) Other delays  
[160] Plus further claims $760,691 for 100 days of extended duration delay that Onespace is  
alleged to have cause due to a variety of design errors and omissions. These are outlined in Scott  
Schedule item no. 3. They include missing gas lines, missing car elevator requiring an additional  
lintel, incorrect detail for a windowsill, incorrect R value for an alcove, required changes to stairs,  
window changes, missing detail for ground fibre wrap at the P4 level, a missing divider on a  
balcony, a car elevator door change, response times to requests for information, inadequate  
personnel, and reviewing poor work.  
[161] I agree with Onespace’s submission that Plus has failed to clearly define alleged design  
errors and omissions, including identifying the specific drawings that are said to contain them, and  
has further failed to tender cogent evidence supporting a finding that Onespace was responsible  
for these items. In addition, Plus has also failed to correlate the alleged errors and omissions to  
the claimed delays. The alleged days of delay are unsubstantiated estimates made by Ali  
Mohtashami himself, albeit reviewed by Martin Gerskup, but which have not been demonstrated  
to have had any impact on the overall project duration.  
[162] There is an important distinction between a delay event and overall project delay.  
A particular activity on a project can be delayed without impacting the overall project duration.  
Since overall project delay is the basis on which Plus advances its claim of $7,606.91 per day, a  
causal link between delays caused or contributed to by Onespace and an extended duration for  
project completion is necessary. Plus has failed to adduce any evidence corroborating delay from  
the alleged errors and omissions.  
[163] Plus has failed to meet its evidentiary onus of demonstrating any breach of contract or the  
standard of care by Onespace supporting liability for alleged project delays.  
iii. Did Onespace fail to coordinate?  
[164] I have found that, although Onespace was not responsible for managing coordination of  
the consultants, it still had an obligation to cooperate in coordinating its own drawings with those  
of others. However, I am satisfied and find that Onespace met the standard of coordination  
required of it. There was no breach of contract by failing to cooperate in coordination.  
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[165] Scott Schedule item nos. 2, 9, 11, and 12 all arise from the mechanical penthouse height  
and roof design issues. Plus alleges that there was a need for upturned beams related to the roof  
cooling tower, that revisions to the mechanical room layout and new roof drawings were required,  
and that additional roof waterproofing costs were incurred. I have already found that Onespace  
did not cause or contribute to the mechanical penthouse and roof design delays. In my view,  
Onespace met the standard of care for coordinating its own drawings and could not reasonably  
have known about the conflicts until raised by Jain. The evidence tendered at trial supports and  
I find that Onespace exercised reasonable judgment, competence, or diligence in responding to the  
conflicts and in coordinating with Jain and CH2M.  
[166] Scott Schedule item no. 8 deals with the need to change the make-up air unit to meet job  
efficiency requirements. Plus has not met its evidentiary onus of demonstrating that the need for  
a change resulted from any failure by Onespace to reasonably coordinate with Jain. Evidence  
supports that Onespace was not responsible for energy modelling. Nothing before me supports  
that Onespace inhibited or delayed information necessary for Jain to determine necessary  
equipment to meet the energy modelling needs of the building. I find that Onespace met the  
standard of care.  
[167] Scott Schedule item nos. 14 and 24 each deal with non-architectural elements that were not  
indicated on drawings of other consultants, namely lack of support for blockwork in a car elevator  
and designs missing necessary fire separation and fire fibre wrap in the northeast shaft. I am  
satisfied from the evidence that these are structural and mechanical elements beyond the scope of  
Onespace’s architectural designs that did not result from any failure by Onespace to coordinate on  
necessary designs. Neither are elements that reasonably needed to be coordinated with  
architectural drawings. Given my finding that Onespace was not required to coordinate other  
consultant’s drawings, I find that it has no responsibility for any errors and omissions in these  
structural and mechanical drawings.  
d. Were there deficiencies in Onespace’s designs?  
[168] In addition to delay, Plus has alleged that various deficiencies in Onespace’s designs  
caused additional costs on the project, namely with respect to a canopy design for the north  
entrance, missing insulation detail, missing structural supports for a stairwell block wall, and an  
incorrect stairwell wall assembly.  
[169] I find no compensable error or omission in Onespace’s designs on any of these issues and,  
accordingly, no breach of contract for design errors or omissions.  
i. North entrance canopy design (Scott Schedule item #15)  
[170] Mr. Mohtashami’s evidence is that a canopy was shown on TACT’s drawings at the north  
entrance, but was not properly designed by Onespace and/or CH2M. Plus incurred an additional  
cost of $5,151 for shop drawings and installation based on Onespace’s sketches, which were  
produced after the project had been tendered. Martin Gerskup confirmed that the north canopy  
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was not detailed in Onespace’s original architectural drawings. Both Mr. Mohtashami and  
Mr. Gerskup also confirmed that the canopy was not priced as part of the project tender. Both  
acknowledged that there would have been a cost associated with it in any event.  
[171] There is no clear evidence from Plus that the north entrance canopy was intended to be or  
requested to be included in the designs, other than the fact that Ali Mohtashami says the canopy  
was included in TACT’s drawings. Onespace ultimately sketched the canopy, but there is no  
specific evidence on the communications leading to that sketch. In my view, Plus has not met its  
evidentiary onus of proving that failing to detail the north entrance canopy was a design error or  
omission. In any event, the claimed damages are unsupported by any cogent evidence.  
ii. Missing insulation detail (Scott Schedule item no. 18)  
[172] Ali Mohtashami’s evidence is that Plus incurred a cost of $16,306.25 for changes to  
insulation required to meet code requirements. His evidence is that Onespace’s drawings for an  
alcove had an incorrect insulation R-value from the fifth floor and up. Required R20 insulation  
details are said to be missing on the drawings and additional insulation was thereby required.  
[173] Plus has tendered no evidence supporting Mr. Mohtashami’s self-serving evidence that an  
incorrect R-value was shown on the drawings and, if it was, that the R-value did not meet code  
requirements. There is no evidence on how and under what circumstances the alleged discrepancy  
was identified and who requested additional insulation. Martin Gerskup’s opinion deals with  
inconsistencies in drawings. His report provides no opinion on the required R-value. Regardless,  
he was tendered as an opinion expert, not a fact witness.  
[174] Plus has failed to meet its evidentiary onus. On a balance of probabilities, I find no design  
error or omission by Onespace.  
iii. Missing structural support for stairwell block wall (Scott Schedule item no. 19)  
[175] Ali Mohtashami’s evidence is that Onespace’s architectural drawings failed to show  
sufficient support detail for stairwell A&B in the building, leading to $46,000 in additional costs  
for redesign, additional support/structural beams, and use of intumesce paint to meet the requisite  
design. However, Vincent Alcaide’s opinion is that Onespace’s permit drawings, tendering  
drawings, and issued for construction drawing all indicate a concrete block dividing wall between  
the stairs extending for the full height of the building, which is a code requirement for the fire  
separation of stairs. He opined that “[t]here is no evidence in the documents [he] reviewed that  
the original concrete block wall could not be constructed with the appropriate steel reinforcing  
required for seismic and structural loadbearing reasons.”  
[176] In my view, Plus has failed to tender cogent evidence on why the change in the assembly  
to a two-hour rated drywall and metal stud fire separation was required and how it constituted a  
design error or omission. Mr. Mohtashami’s affidavit sworn February 3, 2020 points to Pending  
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Change Order #95 as supporting Plus’ claim. However, that change order addresses the fact of the  
change, not the circumstances of or reasons for the change.  
[177] Martin Gerskup’s opinion is that Onespace’s drawings failed to provide any detail for how  
the concrete block wall separating the stairwells was to be supported. During cross-examination,  
though, Mr. Gerskup confirmed that the structural support would not be designed by Onespace. It  
would have been designed by the structural engineer, albeit that Mr. Gerskup’s expressed his view  
that Onespace should have included some indication of supports on its drawings. Nevertheless,  
Mr. Gerskup did confirm that design for the necessary supports was ultimately the responsibility  
of the structural engineer.  
[178] Plus has tendered no evidence on what, if any, coordination was done between Onespace  
and CH2M on these stairs. Plus bears the evidentiary onus of proving that the redesign and  
addition of supports was caused or contributed to by an error or omission in Onespace’s designs.  
Given my finding that Onespace’s coordination was limited to cooperating in coordination with  
affected consultants, the evidence supporting that CH2M had ultimate responsibility for designing  
the structural supports, and the failure by Plus to demonstrate that Onespace’s coordination (or  
lack thereof) fell below what was expected of a reasonably competent architect, I find that, on a  
balance of probabilities, there was no error or omission by Onespace.  
iv. Incorrect stairwell wall assembly (Scott Schedule, item no. 23)  
[179] Evidence on the alleged incorrect wall assembly for the east wall in stairwell A&B was far  
from clear. Ali Mohtashami’s evidence is that Onespace incorrectly detailed the wall assembly,  
requiring a change in wall type to meet required exterior insulation values. Onespace’s drawings  
apparently show an insulated steel P13 wall type, but that was later changed to a EW29A wall  
type, which has a larger metal stud and additional insulation. There is no cogent evidence on the  
reason for that change. During cross-examination, Mr. Mohtashami could not confirm if it resulted  
from a request by the City of Toronto or was triggered by permit review. He did not appear to  
recall or know how the change arose.  
[180] Martin Gerskup’s opinion is that there were several different and inconsistent details for  
the east wall assembly in Onespace’s drawings. He opines that the details reference different wall  
assemblies of different thicknesses, with differing amounts of interior insulation. In some cases,  
the details are said to have failed to include any interior insulation at all. Mr. Gerskup’s view is  
that the inconsistent details fell below the standard of care expected from a professional architect.  
[181] Vincent Alcaide’s opinion is that the drawings showed an insulated steel wall and that the  
reason for change to a EW29A wall type was unclear. He hypothesized that it was likely due to a  
permit review comment made by the City of Toronto requesting a higher insulation for the exterior  
wall. I give little weight to that supposition.  
[182] I am not satisfied that Plus has met its evidentiary onus of demonstrating a breach in the  
standard of care. Mr. Mohtashami’s evidence parrots the opinion of Martin Gerskup, but  
- 33 -  
Mr. Gerskup is an expert, not a fact witness. There is no other evidence on inconsistencies in  
Onespace’s drawings. Although Mr. Gerskup opines that the inconsistencies fell below the  
standard of care, it is not clear to me when the drawings being compared were prepared (the  
extracted drawings in his report are undated) and thereby whether Mr. Gerskup is comparing  
inconsistencies between contemporaneously-prepared drawings or previous and subsequent  
drawings. Necessary factual evidence on what transpired around the change was also not tendered  
through any fact witness.  
[183] The significance of the inconsistency is further unclear. There is no evidence that  
inconsistency led to any confusion on the project. As discussed above, the professional standard  
of care does not require perfection.  
[184] In any event, there is no evidence supporting any actual loss to Plus from the change in  
wall assembly. The claimed $12,000 is entirely unsubstantiated by any documents or other  
evidence. Not even a pending change order was tendered for this item.  
[185] On a balance of probabilities, Plus has failed to prove its claim for the wall assembly  
change. I find that Onespace met the standard of care, but in any event find that Plus has not  
proven that it suffered any loss from the change in wall assembly type.  
Issue 5: Has Plus proved its alleged losses and damages?  
[186] Since I have found that Onespace did not breach the contract and met the standard of care,  
I need not consider whether Plus has proved its alleged damages. Onespace has no liability for  
them. I thereby also need not consider whether Plus caused or contributed to any of its own losses  
or if damages should be apportioned.  
[187] For the reasons set out above, I find that Onespace is entitled to a lien in the amount of  
$55,906.54, including HST, and judgment against Plus in the same amount, plus pre-judgment  
interest. Plus’ set-off claim and counterclaim are dismissed.  
[188] Bills of costs have been exchanged and filed. I encourage the parties to agree on both costs  
and calculation of pre-judgment interest, including a per diem rate that may be applied to the date  
of a report. If they cannot agree on one or both, then written submissions shall be exchanged and  
[189] Onespace shall serve its submissions, including both costs submissions and its position on  
calculation of pre-judgment interest, by October 10, 2022. Plus shall serve his responding  
submissions by October 31, 2022. Onespace shall be entitled to brief reply submissions by  
November 7, 2022. Submissions shall not exceed five (5) pages for primary submissions and two  
- 34 -  
(2) pages for reply submissions, excluding any offers to settle and case law, and shall be submitted  
by email directly to my Assistant Trial Coordinator (ATC), Christine Meditskos, with proof of  
[190] In accordance with the CLA, the results of this trial must be embodied in a report in the  
prescribed form. In the circumstances of this case, a modified form of the prescribed report is  
likely most appropriate. I encourage the parties to discuss an appropriate form of draft report,  
which shall be filed with my ATC by the deadline for reply submissions. If the parties cannot  
agree, then my ATC should be so advised and an appropriate form of report will be addressed  
following my decision on costs and interest.  
September 19, 2022  
CITATION: Onespace Unlimited Inc. v. Plus Development Group Corp.,  
2022 ONSC 5317  
COURT FILE NO.: CV-15-527265  
DATE: 2022 09 19  
IN THE MATTER OF the Construction Act, RSO 1990,  
c. C.30, as amended  
B E T W E E N :  
Plaintiff /  
Defendant by counterclaim  
- and -  
Defendants /  
Plaintiff by counterclaim  
Associate Justice Todd Robinson  
September 19, 2022  

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