Executive Summary: Key Legal and Evidentiary Issues

• Dispute over a residential construction contract for reconstruction of a retaining wall and drainage, including alleged unpaid invoices and claimed overbilling.
• Central technical controversy regarding alleged construction defects, non-compliance with engineering plans, and conformity with the National Building Code in relation to the retaining wall and drainage system.
• Procedural battle over whether the contractor, Monaco, may file a second expert report after the file was ready for trial, and whether that report is a true response to the owner’s expert or an impermissible new opinion.
• Assessment of delay: whether the roughly 19-month gap between the defendant’s expert report and Monaco’s second expert report justifies excluding that late expert evidence.
• Consideration of proportionality, potential prejudice to both parties, and the court’s discretion in managing expert evidence, including whether the defendant should be allowed a further counter-expert report.
• Request for a monetary sanction of $4,000 in extra-judicial fees under article 342 C.p.c., and the court’s refusal to impose such a sanction in light of procedural lapses on both sides.

Factual background

The dispute arises from a residential construction project in Westmount, Quebec. In September 2020, Développement Monaco 2000 Inc. (Monaco) and the homeowner, Earl Luger (Luger), entered into a general contractor agreement for work on Luger’s residential property. The contract covered various works, including the demolition and reconstruction of a retaining wall located in the backyard, as well as related drainage works. Between June and November 2021, Monaco carried out the dismantling and reconstruction of the retaining wall. At the time of reception of the retaining wall work, around 23 November 2021, Monaco maintains that it did not receive any deficiency list from Luger identifying problems with the work. The contractual relationship between the parties ended on or about 15 December 2021. On 8 April 2022, Monaco instituted an action in the Superior Court of Quebec seeking payment on account and damages. Monaco alleged that Luger failed to pay for work performed and services rendered, claiming an unpaid balance of $454,590.51. Luger responded on 24 April 2022 with a defence asserting that Monaco had overbilled and that there were construction defects (malfaçons) in the reconstructed retaining wall.

Procedural history and expert evidence

As the litigation progressed, the case quickly became expert-driven because of the technical nature of the retaining wall and drainage works. On 9 February 2023, Monaco filed a defence to counterclaim and its first expert report from engineer Claude Leguy, dealing with the reconstruction of the retaining wall. On 21 April 2023, the parties executed a revised case protocol. In that document, they agreed that expert evidence was necessary and set deadlines. Luger undertook to produce his expert report by 23 July 2023. Monaco, anticipating a response to any defence expert evidence, expressly reserved its right to file a complementary expert report and/or a counter-expertise once it received Luger’s expert materials. The court later extended the inscription for trial and judgment to 4 October 2023. On that date, Monaco filed a unilateral inscription for trial, signalling that the case was ready to be set down for hearing. Luger then filed an amended defence and counterclaim on 13 October 2023, after the expiry of the protocol deadlines and the inscription date. With those amended pleadings, he also produced additional exhibits and an expert report by engineer François Riopel, which identified alleged deficiencies and specified corrective work required to complete the existing retaining wall and associated drainage works.

Monaco’s attempts to respond to the defence expert

Once it received the Riopel report, Monaco sought to respond on the technical issues raised. It first turned to another engineer, Yvonick Houde, to prepare a counter-expert report on the retaining wall. A formal mandate letter was sent to Houde in March 2024, with an agreed delivery date of no later than 28 June 2024. At a pre-trial conference on 3 June 2024, Monaco advised the court that it was still awaiting its expert’s report. On 12–13 June 2024, the parties signed a joint inscription for trial and judgment, which explicitly contemplated that Monaco would file a second expert report by engineer Yannick (Yvonick) Houde dealing with the drainage of the wall and rainwater collection; a two-hour time slot was reserved for that expert’s testimony. However, despite repeated follow-ups by Monaco and its counsel, Houde did not deliver his report by the agreed date. Faced with this difficulty, Monaco reverted to its original expert, Claude Leguy. On 31 August 2024, it mandated Leguy to answer specific technical questions in light of the Riopel report. A formal mandate letter followed on 1 September 2024. Leguy produced a second report dated 4 April 2025, which was communicated to Luger on 10 April 2025. On 29 May 2025, Monaco formally brought a motion (Demande de bene esse) seeking leave to file this second expert report out of time.

Issues raised regarding the second expert report

Luger opposed the motion, raising several legal and evidentiary objections. First, he argued that the second Leguy report was not a true complementary or responsive expertise. In his view, of the five questions put to Leguy, only one actually answered points raised by the Riopel report; the others either revisited subjects that should have been covered in the first Leguy report or introduced new topics. Luger also argued the report usurped, in part, the court’s role by expressing opinions that were essentially legal conclusions about liability. Second, Luger relied heavily on delay. He emphasized that Monaco took about 19 months from the filing of the Riopel report to communicate its second expert report and contended that no satisfactory explanation had been provided for this lapse. Third, he invoked proportionality and prejudice: permitting a new expert report so late, after the file had been set down for trial, would extend timelines, increase costs, and disrupt the efficient administration of justice.

The court’s legal framework on late expert reports

The Superior Court analyzed the motion through the lens of Quebec civil procedure. The parties’ case protocol was treated as a binding judicial contract, reflecting their agreement on the need for expert evidence and the organization of that evidence under article 232 C.p.c. The court stressed that when asked to allow the late production of an expert report, it enjoys broad discretion under the Code of Civil Procedure, but that discretion must be exercised in accordance with guiding factors developed by the Court of Appeal. Relying on the Modes Striva jurisprudence, the judge recalled that several considerations must be weighed: (1) the reasons preventing timely disclosure of the full evidence; (2) prejudice to the party seeking leave if permission is refused; (3) prejudice to the opposing party if permission is granted; (4) the responsibility of counsel and client for the delay; (5) conduct of the case by counsel since inception; and (6) the sound administration of justice. These factors must be balanced against each other in light of the specific facts, with attention to overarching principles such as proportionality and the broader interest of justice. The court also underlined that excluding an expert report is a drastic remedy, because it removes evidence underpinning a party’s theory of the case. Courts must exercise caution before resorting to such a measure.

Application of the criteria to the second Leguy report

Assessing the substance of the second Leguy report, the judge concluded that it was principally a response to the Riopel report rather than an attempt to introduce a fresh, independent opinion. The expert analyzed and criticized Riopel’s conclusions on alleged non-conformity with engineering plans, the choice between a draining and an impermeable membrane, compliance with the National Building Code, the necessity of a French drain, and alleged premature degradation of the wall. The report addressed new allegations of defects and clarifications that had emerged only through the amended defence and counterclaim and the Riopel report. While some themes overlapped with the first Leguy report, the court found that earlier treatment of these points had been superficial and could not have anticipated all of the detailed criticisms that Luger later advanced. Given the absence of any limitation in the protocol restricting Monaco’s right to a complementary expert report, the court rejected Luger’s argument that the second report impermissibly broadened the scope. On the question of delay, the court noted that Monaco moved quickly to retain Houde after receiving the amended defence and Riopel report. The delay was largely attributable to Houde’s failure to deliver his report by the agreed deadline, and to subsequent practical issues, including family obligations of the expert and an office move by Monaco’s representative. The court considered that the additional ten months between the originally expected filing date (June 2024) and the actual communication of the second Leguy report (April 2025) did not, in the circumstances, justify striking the report—especially as it was still filed some eighteen months before the scheduled October 2026 trial. The court also highlighted that Monaco had consistently signalled its intention to file responsive expert evidence since receiving the Riopel report and amended pleadings. Refusing leave would significantly prejudice Monaco by preventing it from properly answering detailed technical criticisms at the heart of Luger’s counterclaim.

Balancing prejudice, proportionality, and the role of experts

In weighing prejudice and proportionality, the court concluded that any additional costs or inconvenience to Luger from admitting the second Leguy report were outweighed by Monaco’s right to present a full answer to the technical allegations. The judge emphasized that both sides had, at different times, failed to respect protocol deadlines, making it inappropriate to single out Monaco for a harsh procedural sanction. To mitigate any potential prejudice, the court authorized Luger to file a further counter-expertise within 60 days, but limited that report strictly to subjects not already addressed by his existing expert, Riopel. This safeguard allowed the evidentiary record to be balanced without unduly multiplying expert evidence. On the concern that Leguy had exceeded his role by expressing legal opinions, the court reiterated the basic principle that experts must not provide legal conclusions and must confine themselves to their technical sphere to assist the trier of fact. However, this did not lead the court to exclude the report at this stage; rather, it served as a reminder that the trial judge will ultimately control the proper use and weight of expert testimony.

Request for extra-judicial fees under article 342 C.p.c.

In addition to asking for permission to file the second expert report, Monaco sought $4,000 in compensation for extra-judicial fees (essentially its own legal expenses) incurred in presenting the motion. The request was grounded in article 342 C.p.c., which gives courts a discretionary power to impose financial sanctions for serious procedural breaches in order to penalize and deter abusive or improper conduct. The court reiterated that the primary goal of article 342 is to award a sanction proportionate to the gravity of the procedural misconduct and what is fair and reasonable in the circumstances. In this case, the judge refused to grant the requested $4,000. Both parties had deviated from the agreed procedural timetable at various points, including Luger’s late filing of his amended defence and expert report and Monaco’s late responsive report. In that context, the court did not consider it appropriate to single out Luger for a special monetary sanction tied to this motion. The judge left it to the trial judge, who will hear the case on the merits, to assess the parties’ overall procedural conduct and to draw any necessary consequences at the conclusion of the main proceedings, including on costs.

Outcome and identification of the successful party

The judgment is interlocutory and deals exclusively with procedural and evidentiary issues; it does not resolve the underlying construction and payment dispute or Luger’s counterclaim. On the motion, Monaco can be considered partially successful. The court authorizes Monaco to file the complementary expert report of engineer Claude Leguy dated 4 April 2025, thereby allowing Monaco to put forward a full technical response to the Riopel report. At the same time, Monaco’s request for $4,000 in extra-judicial fees is rejected. Luger obtains the right to file a further counter-expert report within 60 days, restricted to points not already covered by his existing expert. As to costs, the court orders that court costs will “follow the event,” meaning they will be determined with the final outcome of the main case rather than at this interim stage. In practical terms, this judgment grants Monaco important procedural relief (authorization of the second expert report) but awards no monetary sum to either party. The total amount of any ultimate monetary award, damages, or costs in favor of the ultimately successful party cannot yet be determined from this decision, and this particular judgment itself orders no specific amount to be paid.