What is a load-bearing wall?

A load-bearing wall carries the structural weight of the building above it, transferring that load down through the foundation to the ground. These walls are typically positioned perpendicular to floor joists or run along the length of the structure. Removing, cutting, or significantly altering a load-bearing wall without proper support can cause sagging floors, cracked drywall, or even partial structural collapse.

Load-bearing walls differ from partition walls, which simply divide interior space and carry no structural weight. You can identify a likely load-bearing wall by its placement along the center of the house (often above a basement beam) or parallel to the roof ridge, but only a structural engineer can confirm this through site inspection.

In Ontario municipalities, including the GTA, you cannot legally alter a load-bearing wall without an approved engineer's design and a municipal building permit. The engineer sizes a properly rated beam (often steel or engineered lumber) to replace the wall's function and specifies support columns or posts at each end. This design is then reviewed during permit inspection, and the installation must be signed off by a licensed tradesperson before walls are closed back up.

When planning renovations that involve interior walls, consulting with a structural engineer early prevents costly rework and ensures your work meets code. Many whole-home renovation contractors in the GTA can connect you with the right engineer or handle the permit process.