When you buy a house, you'll hear about the building inspector (or pre-purchase inspector) and the structural engineer as if they offered the same service. Both can be involved before you sign, but they don't have the same mandate, the same methods or the same professional oversight. Knowing the difference helps you pay for the right service and avoid missing a costly problem.

The building inspector

A pre-purchase inspection is a visual, non-destructive review. The inspector looks at what is visible and accessible on the day of the visit: roof, building envelope, plumbing, electrical, visible structure, signs of water intrusion. You then get a report on the observable condition of the property, prepared according to recognized practice standards.

The inspector doesn't open walls or demolish anything. The inspection covers the whole building rather than one system, which makes it a good way to flag anomalies.

In Quebec, the title of building inspector is not reserved by a professional order. In practice, the market and the courts still expect solid training, membership in a recognized association and professional liability insurance.

When an inspector notices something that goes beyond a visual review, such as a worrying crack, a sagging floor or a bulging wall, good practice is to recommend an assessment by an engineer.

The structural engineer

A structural engineer is a member of the Ordre des ingénieurs du Québec (OIQ), a reserved title regulated by law. You call one in to answer a specific structural question:

  • What is causing this crack, this sag or this deformation?
  • What does it mean for the soundness of the building?
  • What repairs are needed, and in what order?

To answer those questions, the engineer carries out an expert assessment rather than an inspection. That can include measurements, calculations and, when needed, exploratory openings to reach hidden elements. Within their scope of practice, the engineer can also produce signed and sealed plans and calculations, which are required to modify a load-bearing wall or obtain a municipal permit, among other things.

How the two fit together

For most purchases, a pre-purchase inspection is enough. It confirms the overall condition of the building and gives you a clear picture. An engineer comes in when a specific structural question comes up, for example when:

  • the inspector recommends a further structural assessment;
  • you see a horizontal crack, a bulging wall or a crack that seems to be moving (see our article Foundation cracks: should you worry?);
  • a floor is sagging or a frame is deforming;
  • you plan to remove or modify a load-bearing wall after the purchase;
  • you want certainty about the soundness of an element before you sign.

Where AGS fits in

We don't do full pre-purchase inspections. We're the structural specialist your inspector refers you to. When a structural concern comes up, our residential structural assessment gives you a clear diagnosis, the cause of the problem and recommendations ranked by priority. You can then negotiate with the facts in hand or plan your work.

If you're not sure which of the two you need, describe your situation. If a pre-purchase inspection is enough, we'll tell you.

This article is provided for general information. An engineer's scope of practice is governed by Quebec's Engineers Act and the OIQ; pre-purchase inspection follows its own recognized practice standards.