Bulging brick wall: causes, risks and who to call

In Québec, a brick wall that bulges outward is often called a “ventre de bœuf” (ox belly). When the brick is a veneer, meaning a non-structural outer layer connected to the backup wall by metal ties, as CMHC describes it, and that veneer deforms, you need to understand why before choosing a repair. This guide draws on a Canada Mortgage and Housing Corporation (CMHC) publication, the Régie du bâtiment du Québec (RBQ) page Façades – Entretien et inspection (in French) and the City of Montréal page Réparer ou remplacer un revêtement extérieur (in French, updated September 1, 2026), all read on November 3, 2026. It does not replace the opinion of a professional who has seen your wall.

1. What makes a brick wall bulge

In its publication Composite masonry wall ties (Research Highlights, Technical Series 02-109), CMHC explains that steel masonry wall ties may corrode, which can lead to cracking, bulging or even partial collapse of a building’s exterior wall. Even embedded in the wall, the ties are exposed to the moisture and air that get into the mortar; over time they lose their integrity and break. CMHC adds that the problem is usually noticed only once a number of ties have failed, when cracks, a bulge or a partial collapse appear.

The RBQ’s explanatory guide to façade maintenance requirements (in French, revised 2022) lists other factors that wear down cladding:

• orientation: the façades most exposed to the weather are more likely to let water in;
• surroundings: air pollution and de-icing salts, ground movement, deep roots or heavy traffic;
• alterations: the junction between two parts of a building built at different times, or a change of use that adds loads to the structure.

2. Signs to watch for

The RBQ lists signs of deterioration an owner can spot without help: cracks, rust stains, signs of deterioration on balconies, displaced blocks or bricks, and deteriorated joints. It advises recording and dating them to follow how they change. During an inspection, the professional also notes crumbling, efflorescence, spalling, deformations and bulges, then checks hidden components such as lintels and anchors through exploratory openings made on each façade.

3. Why the extent is hard to know

According to CMHC, even with visible symptoms it is difficult to determine the extent of the problem without removing large parts of the wall or doing spot checks with a borescope. Before signing, ask how the company or professional will decide what must be rebuilt: a quote that sets the area to tear down with no prior opening deserves a question.

4. Buildings of 5 storeys or more: specific duties

The Building chapter of Québec’s Safety Code requires owners to check and maintain façades of 5 storeys or more above ground. The owner must obtain a verification report from an architect or engineer no later than the 10th anniversary of construction, then every 5 years, and keep a register on site. If the professional finds a dangerous condition, the owner must notify the RBQ without delay using the prescribed form and, within 30 days, provide a description of the corrective work prepared by an engineer or architect, with a schedule for approval. The guide also describes possible safety perimeters: barriers, nets or scaffolding designed by an engineer. These duties do not cover buildings under 5 storeys, but the RBQ’s list of signs remains a useful checklist.

5. Permits in Montréal

Rebuilding a section of brick is a cladding replacement, often subject to a permit. In Verdun, the City page says a permit is required as soon as a single brick is removed, and that any change must respect the original components. On the Plateau-Mont-Royal, a permit is required for major repairs and to replace the cladding, a lintel or a sill. In Rosemont–La Petite-Patrie, repointing needs no permit, but replacing a wall’s cladding does. Check with your borough’s permit counter before work starts.

6. Who to call

According to Schedules II and III of the Regulation respecting the professional qualification of contractors and owner-builders (B-1.1, r. 9), subclass 4.1, masonry structures, covers structural masonry and exterior masonry veneer walls; subclass 4.2 covers non-structural masonry. For a building of 5 storeys or more, only engineers trained in façade inspection and architects may produce the verification report, according to the RBQ guide. Check the licence of the masonry company before signing. In Montréal’s open permit data (in French), 935 permits issued from October 27, 2025 to October 26, 2026 mention brick, including 173 on the Plateau-Mont-Royal and 140 in Rosemont–La Petite-Patrie. See companies on the Plateau-Mont-Royal, in Verdun or in Rosemont–La Petite-Patrie, or describe your brick wall so licensed companies can reply. See also foundation cracks.