When Do You Need a Structural Engineer?

A structural engineer's job is to make sure a building can safely carry the loads placed on it — its own weight, the people and furniture inside, wind, and in some cases soil pressure. Several common situations should prompt you to involve one.

Adding another floor. Existing foundations and walls are usually designed for a specific load. Before adding a floor, a structural engineer needs to confirm the existing structure can safely carry the extra weight, or specify reinforcement.

Removing or altering a wall. Some interior walls are load-bearing, even if they don't look it. Removing one without an engineer's input is a common and dangerous mistake.

Visible structural cracks. Diagonal cracks, cracks that grow over time, or cracks near windows and doors can be signs of settlement or structural movement that deserve professional investigation.

Building on sloping or poor-quality soil. Unusual site conditions often call for a specific foundation design rather than a standard one.

New multi-storey construction. Any building beyond a simple single-storey structure typically benefits from a formal structural design, both for safety and to satisfy approval requirements.

If you're unsure whether your situation needs one, it's reasonable to ask a structural engineer for a short paid site visit and opinion — far cheaper than discovering a problem after construction.