Catherine DiMarco

Adds value through practical advice and creative solutions.

Catherine DiMarco has more than 17 years of construction and general civil litigation experience.

Certified by the Law Society of Ontario as a specialist in construction law, with a deep understanding of the industry, Catherine provides practical guidance on managing risks during contract negotiations, and assists with project delivery plans.

When disputes arise, she represents different sectors of the construction industry on claims, or on the defence of claims. These include owners, general contractors, subcontractors and suppliers, as well as design and engineering professionals.

Clients appreciate her ability to distill and prioritize key issues and salient facts that arise in complex construction disputes. Her practical and creative approach to dispute resolution is guided by both business drivers and legal remedies.

Catherine has also defended public authorities, including municipalities, in matters involving allegations of negligent design, supervision and inspection.

She regularly attends at the Superior Court of Justice and before arbitrators on a variety of construction and civil matters.

Recognized by the Best Lawyers of Canada™ as a leading lawyer in construction law, Catherine is also a Fellow of the Construction Lawyers’ Society of America. In addition, she is vice-chair and executive member of the Ontario Bar Association Construction and Infrastructure Law Section. Previously, she served as a member of the Executive Committee and Board of Directors of the Canadian Construction Association.

A frequent speaker at industry and client seminars, Catherine has also taught on construction law at the George Brown College School for Architectural Studies and Construction Management and Trades.

She is a volunteer with ProBono Ontario, assisting low-income Ontarians in addressing legal problems that interfere with their ability to lead secure, healthy, and productive lives.
2024 LEXPERT-ranked Lawyer


LL.B., Osgoode Hall Law School (2004)
LL.M., Osgoode Hall Law School (2021)
Certificate in Construction Law, Osgoode Hall Law School (2012)
Trinity College Dublin (First Class Hons.) (2004)
Canadian Aviation Institute (Hons.) (1992)

Called to the Ontario Bar, 2005

  • Chair, Ontario Bar Association, Construction and Infrastructure Law Section Executive
  • Former Vice Chair and Executive Member, Ontario Bar Association, Construction and Infrastructure Law Section
  • Regional Director (Ontario), Society of Construction Lawyers North America
  • Member, American Bar Association
  • Member, Women’s Executive Network
  • Member, Toronto Lawyers Association
  • Member, Law Society of Ontario
  • Past Executive Committee Member and Board Member, and past Vice-Chair, Manufacturers, Suppliers & Services Council, Canadian Construction Association
  • Past Board Member Canadian Association of Women in Construction
  • Past Member at Large, The Advocates’ Society Construction Law Practice Group

  • Speaker, Beware of Legal Gaps and Conflicts: How to Manage Them Using Your Contracts & Subcontracts, 5th Annual Legal Guide to Managing Construction Liens in Ontario, Osgoode Hall Law School – February 2024
  • Instructor, Bidding, Tendering, Leins and Claims, National Edition Fall 2023 Program , Osgoode Certificate in Construction Law – November 2023
  • Speaker, Session 1, Cross-Canada Check In, CBA Construction and Infrastructure Law Conference – October 2023
  • Speaker, Risk Management for Auditors for Construction Contracts and in Construction Litigation, Municipal Internal Auditors Association Fall Workshop and Conference – October 2022
  • Speaker, Managing Construction Liens in Ontario: Managing Legal Gaps and Conflicts in Contracts and Subcontracts, Osgoode Hall Professional Development Seminar – May 2022
  • Co-Chair, Evening with the Construction Bench,  Ontario Bar Association Construction and Infrastructure Law Section – May 2, 2022
  • Speaker, Construction Liens in Ontario: Managing Legal Gaps and Conflicts in Contracts and Subcontracts, 3rd Annual Legal Guide to Managing Construction Liens in Ontario, Osgoode Hall Law School – April 2022
  • Speaker, Ontario’s New Regime for Excess Soil in Construction, Ontario Bar Association Construction and Infrastructure Law Section – December 2021
  • Program Moderator, Trends in Construction Arbitrations, The Advocates’ Society – November 2021
  • Co-Chair, Where the Rubber Hits the Road: Potential Pitfalls along the Road to applying the New Construction Act, Ontario Bar Association – March 2021
  • Speaker, Construction Act Prompt Payment and Adjudication, Ontario Association of Architects – December 2020
  • Speaker, Construction Law Primer, Ontario Bar Association Young Lawyers’ Division – November 2020
  • Goodbye Paper, Hello Technology, Heal & Co. Newsletter – October 2020
  • Speaker, Discerning the Role of Subtrades in the Construction Act- Managing Risk in Construction Contracts and Projects, The Canadian Institute – July 2020
  • Speaker, Building Your Full Circle Leadership”, Toronto Lawyers’ Association Women In Law Program – May 2020
  • Speaker, Coming out of COVID – Litigation in the New Normal, The Advocates’ Society – May 2020
  • Physical Damage as a Trigger for Insurance Coverage, Heal & Co. Newsletter – May 2020
  • Government Clarified Exclusion of Construction Act Deadlines from Emergency Order, Heal & Co. Newsletter – May 2020
  • Speaker, Managing Insurance Coverage and Claims for Losses Arising from the Pandemic, Canadian Construction Association – April 2020

  • Certified by the Law Society of Ontario as a Specialist in Construction Law
  • Recognized as a Leading Practitioner in the area of Construction Law by The Canadian Legal LEXPERT Directory
  • Selected by peers for inclusion in Best Lawyers of Canada™ annually since 2021 in the field of Construction Law
  • Fellow, Construction Lawyers’ Society of America
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