Mark St. Cyr (he/him/his) is a partner at Cassels and serves as Chair of the firm’s national Construction Law Group. He also sits as a member of the Infrastructure Law, Mining Law, and Higher Education Law groups, where he is sought after to facilitate the development of bespoke solutions for construction projects across industries. From the initial concept, through financing, design, procurement and construction, Mark advises clients across Canada and internationally on how to navigate and redistribute project risks.
Mark’s practice includes both “front-end” project structure, delivery, and transaction advice, as well as “back-end” dispute management and mitigation.
Mark’s primary focus is on the “front-end” where Mark advises clients on project structure, procurement, and project delivery models, identifying the best contractual model to suit their project. Mark has the proven ability to turn complexity into concise and straightforward solutions. In addition, he has extensive experience drafting and negotiating all forms of construction agreements, as well as new, innovative, and complex contracts such as alternative financing (P3/PPP), alliancing and integrated project delivery (IPD), progressive delivery models (design-build and construction management), “design-assist,” and “bridging” agreements.
Mark also helps clients navigate in-project and post-completion disputes. As a solutions strategist, Mark is regularly sought out to assess the merits of complex disputes with a view to developing the best go-forward strategy given the strengths and limits of his client’s position as well as their commercial needs. This approach has kept Mark in high-demand to advise both claimants and defendants in a variety of unique construction-related disputes, including integrated project delivery disputes, procurement disputes, bond claims, as well as delay and deficiency claims. Mark’s approach to disputes is to resolutely advance the position of his clients to set up success at trial, while also identifying opportunities for a commercially sensible early resolution.
Recent Representative Work
- Acting as counsel to the project sponsors for the procurements to design, build, and finance over 20 new OPP detachments across the province, including two new regional headquarters (London and Thunder Bay) using a public-private-partnership (P3) model
- Advising the project sponsors on the procurement, design, construction, and financing of the Children’s Hospital of Eastern Ontario (CHEO) 1Door4Care Integrated Treatment Centre project under the public-private-partnership (P3) model
- Advising on and developing a bespoke suite of agreements for the multi-party funding, development, and construction of Canada Games Park in the Niagara Region
- Representing the University of Toronto for the project structuring, procurement and negotiation of the agreements for theirf deep energy retrofit project (Project LEAP), a $138 million public-private project that aims to cut carbon emissions in half on the University’s St. George campus by 2027
- Serving as lead transaction counsel for a university in Ontario in connection with the alternative financing, construction, and operation of a new student residence on its campus as part of Ontario’s “Build Ontario” initiative
- Representing a not-for-profit social housing client, as borrower and owner, in respect of a loan and a design-build agreement under the Affordable Housing Fund program, as part of Canada’s National Housing Strategy. The transaction will result in a project comprising five buildings totaling 261 units of affordable housing to be available for occupancy starting in 2027
- Acting for a mining company in the negotiation of a target price contract for steel, mechanical, and piping works related to the development of a gold mine in Newfoundland
- Lead implementation counsel for a municipality in respect of all land, development, infrastructure, and construction matters for a new LRT line being developed pursuant to the design-build-finance-operate-maintain delivery model, including the detailed negotiation of the implementation agreement as between HMQ and the municipality
- Ongoing mandates for post-secondary institutions, municipalities, regional governments, boards of education, contractors, subcontractors, and suppliers to update their current contracts to keep pace with market conditions, address legislative changes (e.g., Construction Act updates), manage global phenomena (e.g., COVID-19 and supply-side risks), and to redistribute risk based on the latest jurisprudence
Selected Speaking Engagements
- Transit Procurement and Delivery – Lessons Learned from Collaborative Models, Canadian Institute’s Urban Transit Infrastructure Symposium (Vancouver, June 2025)
- Hot Topics: Cassels Construction Law Update (Cassels Academy, May 2025)
- Contract Negotiations, Royal Architectural Institute of Canada, Law and Practice Webinar Series (National, Online April 2025)
- R v. Sudbury: Impacts of the Supreme Court decision on OASBO contracts, Ontario Association of School Business Officials (Blue Mountain, July 2024)
- Collaborative Project Delivery Models, Canadian Bar Association Construction and Infrastructure Section (Vancouver, October 2023)
- From P3 to IPD: Using the Contract to Mitigate Healthcare Project Risks and Disputes, Canadian Institute (Toronto, November 2022)
- Reinforcing the Foundations: Legal Fundamentals for the Construction Industry (Cassels Academy, February 2022)
- Updating the CCDC 2 – 2008 Stipulated Price Contract: Review of Key Revisions to Supplementary Conditions, Ontario Association of School Business Officials (Niagara Falls, November 2020)
- Navigating the New Construction Regime in Ontario:
Understanding Key Changes in the Construction Act, Electrical Contractors Association of Ontario (Toronto, November 2019) - Select Client Seminar Topics (2020 to present): CCDC 5B Contract Playbook; CCDC 2 Contract Playbook; OAA 600 Contract Playbook; Duty of Good Faith in Tendering; Protection During Procurement: An ounce of prevention is worth a pound of cure; Understanding Key Changes to the Prompt Payment and Construction Lien Act (Alberta); Protecting Against Procurement Pitfalls; The Construction Act – Revisiting the Fundamentals; Changes in Construction Contracts; Teamwork Makes the (Project) Dream Work: An Owner’s Perspective on Collaborative Project Delivery; Effectively Managing Project Claims; The Basics of Public Procurement
Selected Publications
- Cassels Construction Notes: Sudbury Saga Finale (April 2025); New Tariffs Certain to Tax the Construction Industry (March 2025); Don’t Hold Back (For More Than a Year): Mandatory Annual Holdback Release and Other Updates to the Construction Act (December 2024); Don’t “Talk the Talk” If You Won’t “Walk the Walk”: Oral Agreements May Constitute Binding Contracts (November 2024); Due Diligence Deliverance: Court Upholds Due Diligence Defence in R. v. Greater Sudbury (August 2024); Waiver by Conduct: Actions May Speak Louder Than Words (March 2024); Payment Under Protest: Payments With No Pride and No Prejudice (February 2024); A Two-Way Street: Owners May Be Liable for Health & Safety Compliance as “Employers” Under the OHSA (January 2024)
- Other Written Insights:
- Co-Author, OBA Article: “Ontario the Outlier: An Analysis of the Integration of the Lien and Adjudication Regimes under the Construction Act” (May 2023)
- Co-Author, Thomson Reuters Practical Law, Construction and Projects: Overview (Canada) (2019-present)
- Contributing Editor to the forthcoming 4th Edition of Kirsh and Alter: A Guide to Construction Liens in Ontario
Prior to becoming a lawyer, Mark was a crime analyst with the Royal Canadian Mounted Police, based in North Vancouver, British Columbia.
