Foundation Repair in Southern Ontario: A Homeowner's Guide

Most foundation cracks in Southern Ontario are not emergencies, and a few are. The hard part is knowing which one you have, and then buying the right fix for it rather than the biggest one or the cheapest one. This guide takes the decisions in the order you should make them. For the work itself, see our foundation repair service.

Step 1: Read the crack before anything else

Look at four things and write them down.

• Width. A hairline under 1/8 in. is usually shrinkage. A crack past 1/4 in. deserves attention.
• Direction. Vertical and slightly diagonal cracks in a poured wall are the common kind. A horizontal crack in a block wall means soil pressure, and it goes on the serious list.
• Movement. Mark both ends with a pencil and date them. A crack that grows over a season has a live cause. Our guide to a foundation crack that keeps getting wider shows how to watch it.
• Offset. If one face of the crack sits proud of the other, the wall has shifted, not only shrunk.

Add a fifth note: does water come through? A dry crack and a leaking crack get different repairs.

Step 2: Find the cause, not only the crack

A crack is a symptom. The clay soils across much of Southern Ontario hold water and swell, and block walls take that pressure sideways. That is where bowing and stair-step cracks come from. Most of the water comes from close to the house: a downspout that empties at the corner, ground that slopes toward the wall, or weeping tile that no longer drains.

Fix the cause with the crack. A sealed crack in a wall that clay still pushes on can move again.

Step 3: Match the repair to what the crack is doing

Each kind of crack has a usual fix.

• A crack that leaks. Polyurethane injection. It expands on contact with water, fills the crack through its full depth, and stays flexible as the wall moves with the seasons.
• A dry crack you want strong again. Epoxy injection. It bonds the two faces back into one wall. It is the right choice when strength matters and the water is already dealt with. Our epoxy and polyurethane comparison goes deeper.
• A block wall with a moderate bow. Carbon fibre straps, epoxied to the wall and anchored top and bottom, usually one every 4 to 6 ft. They stop more movement. They do not pull the wall straight. The working rule is a bow under about 2 in.; past that, steel bracing or rebuilding sections comes into the conversation.
• Water through several cracks or the whole wall. This is no longer a crack repair. It is basement waterproofing, and the cause outside the wall is part of the job.
• A crack only in the parging. The thin coat on the exposed band cracks with weather on its own. If the crack stops at the coat, it is a parging job. If the wall is cracked under it, fix the wall first and parge after.

One fix to avoid: hydraulic cement or caulk smeared over the inside face of a leaking crack. It plugs the surface while the crack behind it stays wet, and freeze-thaw opens it again.

Step 4: Check who pays and what paperwork applies

Two questions come before you sign.

• Is the house new enough for the new-home warranty? Ontario’s new-home warranty (Tarion) covers water coming through the foundation for two years and major structural defects for seven. Inside those windows, the builder may owe you the repair. Call them first.
• Does the work need a permit? Underpinning builds new footings below the old ones, and it needs a building permit. In Toronto, a professional engineer is required in some cases, for example where the soil is clay or silt. Each municipality sets its own process, so call your building department before structural work starts. Underpinning is rare in ordinary houses, and no quote should start there without measurements you can see.

Step 5: Ask any contractor these questions

A good quote answers them before you ask. Make sure each quote you get says:

• what the crack is doing (width, direction, movement, offset) and how they measured it;
• whether the repair is a seal, a structural repair, or water management, and why;
• which material they will use (polyurethane, epoxy, carbon fibre) and why that one fits;
• for straps, the count and the spacing, so you can check the math against another quote;
• what they will do about the cause outside the wall: grading, downspouts or drainage;
• whether the injection fills the crack through its full depth, not only the surface;
• what the warranty covers, in writing.

If a quote calls a hairline a structural emergency, ask to see the evidence. If the honest answer is “watch it for a year”, a good contractor says so.

What drives the cost

We do not publish prices, because the honest number depends on your wall. A single crack injection is at the small end of foundation work, and several cracks in one visit usually cost less each. The cost climbs with the number of cracks, a structural repair instead of a seal, carbon fibre straps, and water management outside the wall. Our foundation crack repair cost guide explains each factor.

We look at your wall for free and give you a written quote with a reply within one business day. The labour carries a lifetime warranty. When you are ready, ask for a free written quote.