Expertise
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Practice Areas:
- Bar Admissions:
- Education:
- Osgoode Hall Law School (2012) JD
- University of Western Ontario (2007) BSc (Civil and Environmental Engineering)
Details
- Bio
- Cases
- Associations
- News & Media
- Publications & Presentations
- Recognition
Aaron I. Grossman (he/him)
is a partner at Lenczner Slaght.
Aaron’s practice focuses on litigating disputes within the construction, infrastructure and real estate sectors. With significant expertise as a lawyer and structural engineer, Aaron excels in highly technical cases which require expert evidence. He can speak the same language as engineering and construction professionals allowing for efficient and successful representation of his clients from the outset of a matter through to trial.
Aaron has significant experience advising clients on claims and issues that arise during the course of a project under a number of different contract models. Aaron’s deep experience in the construction industry allows him to get up to speed quickly and provide timely and practical advice to his clients.
Aaron is experienced in resolving complicated engineering and construction by negotiation, mediation, and arbitration. Aaron is highly skilled at developing custom dispute resolution processes to advance his clients’ interests effectively and quickly. Clients look to Aaron for strategic and practical advice to resolve their technical legal disputes in the courtroom and the boardroom.
Prior to attending law school, Aaron studied and practiced structural engineering, concentrating on building design and construction.
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Confidential Construction Arbitration
Counsel to a contractor against a sub contractor in a confidential construction arbitration relating to negligence, breach of contract, and damages arising from deficient installation of shoring and foundation systems.
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Romspen Investment Corporation v Woodbine Mall Holdings Inc et al
Counsel to the responding party in a three-day trial of issues conducted under the Bankruptcy and Insolvency Act.
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Aecon v K+S Potash Canada GP and K+S Legacy GP Inc (Third Party Claim)
Counsel to Aecon in a third party claim against Aecon relating to alleged design and construction deficiencies in the process plant for a $4 billion solution potash mine in Saskatchewan.
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10390160 Canada Ltd et al v Casey et al
Counsel to a number of investors in a limited partnership commencing an action for breach of contract and seeking a Mareva injunction against the Defendants.
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Crosslinx Transit Solutions Constructors v Form & Build Supply (Toronto) Inc
Counsel to Crosslinx Transit Solutions Constructors in a successful motion to declare a lien from a sub-subcontractor expired. The decision was the first to consider and apply the transition provisions in the Construction Act, R.S.O. 1990, c. C.30 to the time limit to register a lien.
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Counsel to various stakeholders in competing applications for the appointment of a receiver and manager pursuant to subsection 243(1) the Bankruptcy and Insolvency Act, section 101 of the Courts of Justice Act, and an application for protection under the Companies’ Creditors Arrangement Act.
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Counsel to a general contractor in respect of a complex mediation/prospective arbitration process regarding a subway extension project.
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Counsel to a general contractor in a dispute with a design subcontractor on a very large transit project regarding design deficiencies and payment for design changes that have arisen over the course of construction.
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Aecon Mining Construction Services v K+S Potash Canada GP
Counsel to Aecon in complex litigation involving multiple parties and claims, in respect of the Legacy potash mine and production facility in Saskatchewan.
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TSCC 2282 v Bay-Yorkville Developments
Counsel to the defendant developer in proceedings alleging construction deficiencies in the construction of the Four Seasons Residences in Toronto.
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The Advocates’ Society - Member-at-Large of the Construction Law Practice Group (2024-2026)
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Law Society of Ontario
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Ontario Bar Association
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Lenczner Slaght Celebrates 25 Years on the Lexpert Bull’s-Eye
The 2026 Canadian Legal Lexpert Directory continues to recognize Lenczner Slaght as the #1 firm in Toronto for Litigation and Commercial Litigation.
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Lenczner Slaght Recognized in Legal 500 Canada for Litigation Excellence
As Canada’s leading litigation firm, we are proud to maintain our Tier 1 ranking in Dispute Resolution in Legal 500 Canada.
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Chambers Canada Highlights Lenczner Slaght’s Excellence in Advocacy
Canada’s leading litigation firm continues to be recognized in world-renowned directory, with new rankings highlighting its deep bench of expertise.
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Lenczner Slaght Litigators Featured Among Best Lawyers in Canada
The 2026 edition of Best Lawyers in Canada recognizes Lenczner Slaght with 180+ rankings, featuring 48 of our expert litigators across 27 practice areas.
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7 Lenczner Slaght Litigators Appointed to Leadership Roles in The Advocates’ Society
As recognized leaders of the bar, our lawyers will help advance the mission of Canada’s leading organization for litigators – fostering a national, collegial community of advocates committed to excellence inside and outside the courtroom.
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2025 Lexpert Directory Highlights Lenczner Slaght’s Excellence in Advocacy
Peers and senior members of the legal profession across the country continue to recognize the depth and breadth of Canada’s leading litigation firm in the latest 2025 Canadian Legal Lexpert Directory.
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Lenczner Slaght Welcomes New Partners in Construction & IP
Canada’s leading litigation firm is proud to announce that two of our expert litigators, Aaron Grossman and Martin Brandsma, have been promoted to the partnership.
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Lenczner Slaght Litigators Recognized as the Best Lawyers in Canada
In the 2025 edition of Best Lawyers in Canada, Lenczner Slaght is proud to receive 168 total rankings, with 45 of our expert litigators recognized for their expertise across 25 practice areas.
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Lenczner Slaght Litigators Elected to The Advocates’ Society’s Leadership
We are pleased to announce that Sahar Talebi, Aoife Quinn, Aaron Grossman, Christopher Yung, Paul-Erik Veel, and Andrew Parley will be serving prominent leadership positions at The Advocates’ Society, a preeminent organization dedicated to promoting effective advocacy and access to justice.
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The 2024 Lexpert Directory Recognizes Lenczner Slaght’s Litigation Excellence
Lenczner Slaght’s litigators continue to be recognized by their peers as the foremost practitioners in their fields.
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Managing Risk at Ground Level: Perspectives on Geotechnical Investigations
Aaron will present on the panel titled, Managing Risk at Ground Level: Perspectives on Geotechnical Investigations at The Canadian Geotechnical Society Southern Ontario Section's Dinner Lecture & Student Poster Competition. Aaron will share his expertise on the legal and practical project challenges in geotechnical investigations, including how subsurface uncertainty is identified, allocated, and managed, as well as recurring themes that can lead to geotechnical disputes.
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2025 Snapshot: Through the Lens of Lenczner Slaght
We’ve released our 2025 Snapshot, highlighting the most significant developments, decisions, and trends in litigation from the past year across 21 practice areas. Reflect on 2025 and look ahead to 2026 through the lens of our expert litigators.
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Aaron Grossman was invited to share his expertise on the Royal Architectural Institute of Canada's webinar series, Resilient Architect: Law and Practice. Aaron discussed common dispute resolution provisions in RAIC and CCDC contracts, examining how legal authorities interpret them and how statutory adjudication varies by province. He also covered key methods such as mediation, arbitration, and litigation, and their impact on outcomes across jurisdictions.
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2024 Snapshot: Through the Lens of Lenczner Slaght
Lenczner Slaght launches our 2024 Snapshot, which highlights the most significant developments, decisions, and trends in litigation from the past year across 20 areas of expertise. Reflect on 2024 and look ahead to 2025 through the lens of our expert litigators.
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Litigating or Arbitrating Complex Construction Disputes
Aaron Grossman was invited to co-chair The Advocates' Society's program titled Litigating or Arbitrating Complex Construction Disputes. Aaron led a discussion on the pros, cons, and everything in between when it comes to litigating or arbitrating complex construction disputes.
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2023 Snapshot: Through the Lens of Lenczner Slaght
Lenczner Slaght launches our 2023 Snapshot, a look at the most significant developments, decisions, business takeaways, and trends in litigation from the last year, across 15 practice areas. Revisit 2023 and look ahead to 2024 through the lens of our expert litigators.
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Why the Construction Act’s transition provisions are still important 3 years later
Aaron I. Grossman and Brianne Westland authored the article Why the Construction Act’s transition provisions are still important 3 years later, which was published by On-Site Magazine.
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Best Lawyers in Canada (2021-2026)
Alternative Dispute Resolution, Construction Law, Corporate & Commercial Litigation
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Canadian Legal Lexpert® Directory (2024-2026)
Construction Law, Litigation - Corporate Commercial
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Chambers Canada (2026)
Construction (Nationwide – Canada)
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Lexpert Special Edition: Canada's Leading Infrastructure Lawyers (2025-2026)
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The Legal 500 Canada (2026)
Construction (Next Generation Partner)