Why Some Provinces Require a Pre-Construction Survey

A pre-construction, or pre-servicing, survey establishes the precise legal boundaries of a lot and the location of existing features against those boundaries before construction begins. It's a different exercise from the site plan submitted with a permit application — that plan is proposed, while a survey confirms the physical reality on the ground.

It matters most on infill lots, additions close to a property line, or anywhere the setback margin is tight, since a foundation poured a foot into the wrong spot can be an expensive problem to fix after the fact. Some municipalities require a surveyor's certificate confirming the foundation location before framing is allowed to proceed, catching the error at the cheapest possible stage.