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Lianne J. Armstrong

Partner

Lianne is a senior construction and commercial litigator who helps businesses resolve complex disputes involving contracts, projects, facilities and operational risk. With deep manufacturing and construction industry experience, she provides practical, strategic advice focused on protecting business interests, minimizing disruption and reaching cost-effective resolutions.

Areas of Expertise

  • Commercial & Contract Disputes – Litigation, mediation and arbitration involving commercial agreements, project relationships, payment claims, business risk and disputes affecting operations.

  • Construction Dispute Resolution – Strategic representation in mediation, arbitration, adjudication and litigation, with a focus on resolving disputes efficiently and minimizing business disruption.

  • Construction Contract Drafting & Negotiation

  • Commercial, Project & Contract Disputes

  • Construction Dispute Resolution

  • Project Risk Management

  • Procurement & Tendering Disputes

  • Delay & Disruption Disputes

  • Construction Liens & Payment Remedies

  • Deficiency & Defect Claims

  • Bond & Surety Claims

Education

  • Admitted to Ontario Bar (1998)

  • Bachelor of Laws, Queen’s University (1996)

  • Bachelor of Arts (Hons.), University of Windsor (1998)

Noteworthy Cases

  • Liora Fine Arts Inc. v. Malcolm Holdings Inc., 2016 ONSC 8103
    In this construction dispute, the Court denied a motion to substitute a defendant's name, ruling that there was no misnomer and dismissing claims against a defendant personally. The case clarified the test for misnomer and piercing the corporate veil, upholding the principle that personal liability of corporate officers cannot be imposed without sufficient evidence.

  • Soan Mechanical Ltd. v. Terra Infrastructure Inc., 2011 ONCA 371
    This construction case dealt with breach of contract and the quantum meruit principle. The Ontario Court of Appeal upheld the trial decision in favor of the respondent, clarifying the proper scope of damages in cases of incomplete performance or breach of contract.

  • 2021977 Ontario Inc. v. Shadamy Holdings Company, 2006 CanLII 31810 (ON CA)
    The Ontario Court of Appeal upheld the trial decision concerning insurance exclusions and the validity of claims under a property contract. This case is notable for reinforcing principles related to contract law and insurance coverage exclusions in complex property disputes.

  • Kavanaugh v. Knol, 2006 CanLII 815 (ON SC)
    In this estate litigation case, successfully argued for the application of equitable remedies in the face of disputes over will validity and insurance proceeds. The decision reinforced the necessity of full disclosure and good faith in matters related to estate administration and insurance.

  • Padelt v. Show Fong Lu, 2010 ONCA 69
    The Court of Appeal upheld the trial judge’s finding that the mortgagee met their duty of maintenance before the sale of a property, confirming that a mortgagee is not liable for negligence if they act as a reasonable, prudent property owner. This case emphasized the scope of a mortgagee’s duty to maintain a property and the standards for liability in property management.

  • Magil Construction Canada v. JBelli Holdings, 2023 ONSC 1837
    This case dealt with third-party claims and the complexities of party additions and counterclaims in construction disputes. It clarified the requirements for amending pleadings and adding parties under Ontario’s Rules of Civil Procedure, reinforcing procedural rules in construction litigation.

  • St. Lawrence Neighbourhood Association v. Ontario (Minister of Government and Consumer Services), 2021 ONSC 1087
    This case involved a judicial review of a government decision under the Heritage Act. The Ontario Divisional Court’s decision clarified the boundaries of administrative law and the judicial review process in relation to heritage preservation, emphasizing the legal protections for heritage sites and the roles of government ministries in making decisions about public spaces.

  • Farwell v. Citair, Inc., 2014 ONCA 177
    The Court of Appeal upheld the constructive dismissal of an employee who was demoted to a significantly lower position, affirming that this constituted a fundamental breach of the employment contract. A key principle in this case is that constructive dismissal occurs when an employer makes a fundamental change to the terms of an employee’s contract without proper notice. The appeal also addressed mitigation principles, finding that the employee’s refusal to accept the demotion was reasonable given the humiliation involved, and the employer’s failure to offer a clear notice period meant that no mitigation obligation was breached.

  • Van Geel v. Pennha, 2020 ONSC 6975
    Successfully moved to discharge a Certificate of Pending Litigation obtained without full and fair disclosure. Protected the client’s property interests and helped clarify the limits on using CPLs when construction lien rights have expired.

Memberships

  • Executive member of Board of Directors of London & District Construction Association

  • The Advocates’ Society

  • Canadian Bar Association

  • Past President Southwest Regional Women’s Law Association

  • Past President of Middlesex Law Association

Construction and Commercial Litigation

Lianne Armstrong is a partner in Lerners’ London office, a member of the firm’s Dispute Resolution and Advocacy Group, and Leader of the Construction Law and Disputes Group. Her practice is grounded in construction law and dispute resolution, including matters involving project delivery, contracts, procurement, delay, deficiencies, and construction liens. She also represents manufacturers and other businesses in related commercial disputes involving industrial facilities, capital projects, contractual relationships, and operational risk.

With close to 30 years of experience, Lianne understands how construction and commercial disputes can affect schedules, capital investment, supply relationships, and day-to-day operations. She works with owners, developers, general contractors, subcontractors and businesses, including manufacturers investing in new facilities, plant expansions, renovations, and other capital projects.  

Lianne advises clients throughout the lifecycle of a construction project, from contract drafting and risk allocation to dispute prevention and formal proceedings. Her work includes procurement and tendering disputes, contract interpretation and enforcement, delay and disruption claims, construction liens, deficiencies, payment disputes and disputes involving contractors, suppliers and project partners. She also assists manufacturers and facility owners with commercial disputes arising from construction projects, facility investments and contractual relationships that affect operations.

For manufacturers, construction and commercial disputes often extend beyond the immediate legal issue. A delay, deficiency, payment dispute or breakdown in a project relationship can affect production schedules, capital investment and operational continuity. Lianne brings a construction-law perspective to these matters while helping clients pursue practical resolutions aligned with their broader business priorities.

Known for her practical and strategic approach, Lianne helps clients identify a path that aligns legal strategy with their business objectives. She focuses on protecting the client’s position, managing risk and resolving disputes as efficiently as the circumstances allow.

As a board member of the London and District Construction Association, Lianne stays connected to developments affecting construction, infrastructure and facility projects. She draws on that industry perspective to provide commercially grounded advice to clients managing disputes, project risk and operational priorities.

Lianne is an Assistant Professor at Western Law. In her spare time, she enjoys running, golfing and travelling.

Lianne Armstrong is a partner in Lerners’ London office, a member of the firm’s Dispute Resolution and Advocacy Group, and Leader of the Construction Law and Disputes Group. Her practice is grounded in construction law and dispute resolution, including matters involving project delivery, contracts, procurement, delay, deficiencies, and construction liens. She also represents manufacturers and other businesses in related commercial disputes involving industrial facilities, capital projects, contractual relationships, and operational risk.

With close to 30 years of experience, Lianne understands how construction and commercial disputes can affect schedules, capital investment, supply relationships, and day-to-day operations. She works with owners, developers, general contractors, subcontractors and businesses, including manufacturers investing in new facilities, plant expansions, renovations, and other capital projects.  

Lianne advises clients throughout the lifecycle of a construction project, from contract drafting and risk allocation to dispute prevention and formal proceedings. Her work includes procurement and tendering disputes, contract interpretation and enforcement, delay and disruption claims, construction liens, deficiencies, payment disputes and disputes involving contractors, suppliers and project partners. She also assists manufacturers and facility owners with commercial disputes arising from construction projects, facility investments and contractual relationships that affect operations.

For manufacturers, construction and commercial disputes often extend beyond the immediate legal issue. A delay, deficiency, payment dispute or breakdown in a project relationship can affect production schedules, capital investment and operational continuity. Lianne brings a construction-law perspective to these matters while helping clients pursue practical resolutions aligned with their broader business priorities.

Known for her practical and strategic approach, Lianne helps clients identify a path that aligns legal strategy with their business objectives. She focuses on protecting the client’s position, managing risk and resolving disputes as efficiently as the circumstances allow.

As a board member of the London and District Construction Association, Lianne stays connected to developments affecting construction, infrastructure and facility projects. She draws on that industry perspective to provide commercially grounded advice to clients managing disputes, project risk and operational priorities.

Lianne is an Assistant Professor at Western Law. In her spare time, she enjoys running, golfing and travelling.