A Basement That Needs to Be Lowered

This guide does not diagnose your foundation. It helps you decide who to call and what to ask.

There are two common ways to get more headroom. Underpinning extends the foundation down under the existing footings. A bench footing leaves the existing footings and steps the new floor down inside them.

Both are structural work. Engineering and a building permit are often part of the project, and the rules come from your municipality.

Get it looked at soon if

You are planning a basement suite and need a minimum ceiling height.
The existing foundation has cracks, water or movement.
Neighbouring houses are close to or share a wall with yours.

If you think there is an immediate safety risk, leave the area and contact your local emergency services.

Who can assess it

A structural engineer

Independent of any contractor. Can assess whether there is a structural problem and write a repair scope that contractors then price.

An underpinning contractor

Can look at the problem and propose a repair. They sell the repair, so ask what else could explain what you see.

A designer or architect

Prepares the drawings your municipality reviews for the building permit. Contractors price the foundation from those drawings.

Services that may come up

Questions to ask every contractor

Underpinning or bench footing for this house, and why?
Who provides the engineered drawings, and who applies for the permit?
How is the work done in sections, and how long will the basement be unusable?
Does the price include new drainage, the slab, waterproofing and disposal?
What happens if the soil or water conditions are different from what you expect?
What does the warranty cover?

What to record

Keep the engineer's drawings and any permit with the contract.
Photograph the basement and neighbouring walls before work starts.
Keep every change order in writing.

Slow down if you hear

Pressure to sign today or lose a price.
A large deposit before any work or materials arrive.
A scope that does not say what is included.
Claims of a grant or rebate you cannot confirm yourself.