By: Catherine Ramsay-Piérard, Lawyer, and Louisa Kouretas, Articling Student

Must a Building Be at Risk of Collapse to Constitute a “Loss of the Work”?

The Often-Overlooked Scope of Article 2118 C.C.Q.

October 21, 2026

The Civil Code of Québec (the “CCQ”) provides that contractors, architects, engineers and professional technologists who, as the case may be, directed or supervised construction work, as well as subcontractors who performed such work, are presumed solidarily liable for the “loss of the work” occurring within five years following the completion of the work, unless they can be relieved of their liability.

In other words, where a work suffers a premature loss within the first five years following its completion, a presumption of liability applies to the contractor, architect, engineer and professional technologist, to the benefit of the client. As this provision is a matter of public order, the client cannot waive this protection in advance.

To determine whether this presumption of liability applies, it is first necessary to establish whether a “loss of the work” has actually occurred.

The concept of “loss of the work” has been the subject of numerous judicial interpretations and involves several important nuances. Contrary to what one might intuitively assume, it is not limited to situations where a building collapses or its structural integrity is irreparably compromised.

It is also worth noting that, given the presumption of solidary liability among the various parties involved, the question is no longer simply one of determining who committed the fault.

It is therefore important for those concerned to understand the scope of this concept, which can have significant implications for their business activities.

The Presumption of Liability in the Event of Loss of the Work

Under the CCQ, a “loss of the work” may result, among other things, from a defect in the design, construction or execution of the work, or from a defect in the ground.

This concept therefore concerns problems that are more serious than minor defects or deficiencies in workmanship, which are notably covered by the separate warranty regime provided for under article 2120 CCQ. The question, however, is where the line should be drawn between these concepts.

The Concept of “Loss of the Work”: Beyond Collapse

The courts have long adopted a broad interpretation of the concept of “loss of the work”, which does not necessarily require a total loss, but may encompass a partial or even potential loss of the work. In certain specific circumstances, a loss may even consist of the mere loss of the normal use of the work, and may affect a building that remains occupied.

Depending on the circumstances, permanent deficiencies, significant structural problems or water infiltration may constitute a loss of the work and thereby trigger the presumption of liability.

The concept of loss must be interpreted in conjunction with that of a defect. A defect that creates a serious and real risk that a work may collapse, subside, sink or fall, in whole or in part, or that compromises its structural integrity, may give rise to a “loss” within the meaning of the CCQ. In Installations GMR inc. c. Pointe-Claire (Ville de), the Court of Appeal reiterated that, in certain circumstances, serious defects causing significant inconvenience and rendering the work unfit for its intended purpose may constitute a loss.

Conversely, not every deficiency constitutes a loss of the work. It is therefore important not to conclude too hastily that the presumption of liability applies.

The decision in Assistance aux femmes de Montréal inc. c. Habitations Alexandre inc. provides a compelling illustration of the concept of “loss of the work”. In that case, the evidence revealed, among other things, deflection of wooden framing components, sagging floors, doors that would stick seasonally and cracks in load-bearing walls. Corrective work and structural modifications were required. The Superior Court concluded that the defects were sufficiently serious to affect the stability of the building and to qualify as major defects, even though they were not likely to cause its ruin or collapse.

The relevant question is therefore whether the deficiency is sufficiently serious to compromise the integrity, stability or, in certain cases, the normal intended use of the work. A client does not always have to wait for a catastrophic event to occur before seeking to benefit from the presumption of liability in their favour.

Addressing the Presumption of Liability

The CCQ sets out the circumstances in which the various parties involved may be relieved of their liability.

An architect, engineer or professional technologist may be relieved of liability only by proving that the defects in the work, or in the part of the work they performed, do not result from any error or defect in the expert opinions or plans they provided, or from any failure in the direction or supervision of the work. A contractor, on the other hand, may be relieved of liability only by proving that the defects resulted from an error or defect in the expert opinions or plans of the architect, engineer or professional technologist selected by the client. Finally, a subcontractor may be relieved of liability only by proving that the defects resulted from decisions made by the contractor or from the expert opinions or plans of the architect, engineer or professional technologist.

In all cases, each of these parties may be relieved of liability where the defects result from decisions imposed by the client concerning the choice of ground or materials, or the selection of subcontractors, experts or construction methods.

The role actually performed by each professional therefore remains a determining factor in assessing liability. In this regard, the Court of Appeal has referred to the principle of “primary fault” (faute première), according to which liability arising from the improper execution of construction work should, in principle, be borne by the contractor or subcontractor who performed the work, rather than by the professional responsible for supervising it.

This principle does not, however, exclude a professional’s liability for their own distinct fault, particularly where such fault arises from the design of plans or recommendations made in the course of their mandate. Moreover, where an architect, engineer or professional technologist has neither directed nor supervised the work, their liability is limited to losses resulting from a defect or error in the plans or expert opinions they provided.