Crack injection

Foundation crack injection in Durham Region

Injection is the standard fix for a leaking or cracked poured-concrete basement wall. It's done from inside in a few hours, with no digging. Here's how it works, which material fits your crack, and what it costs.

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How crack injection works

Assessment: the contractor checks the crack type, width, whether it's active, and whether the wall is poured concrete (injection works) or block (usually doesn't).
Prep: the crack face is cleaned and injection ports are set every 20–30 cm along it.
Surface seal: the crack is sealed over on the inside face so material can't escape.
Injection: material is pumped in from the lowest port upward until it pushes through the full wall thickness to the soil side.
Finish: after curing, the ports are cut flush. The wall can be refinished.

Epoxy or polyurethane?

	Polyurethane	Epoxy
Best for	Leaking or damp cracks, waterproofing	Dry cracks where you want strength restored
How it works	Expands into foam that fills the crack and blocks water	Cures rigid and bonds the two sides back together
Handles movement	Yes, it stays flexible	No, it's rigid, and a new crack can form beside it
Wet crack?	Yes	Needs a dry crack
Typical price	Lower	Higher

For most leaking basement cracks in Durham, polyurethane is the standard choice. Epoxy is used when an engineer or contractor wants the wall's strength restored, for example on a dry structural crack.

What crack injection costs around Durham

Job	Typical cost (CAD, 2026)
Polyurethane injection, one crack	$750 – $1,000
Structural epoxy injection, one crack	$850 – $1,500
Actively leaking crack plus interior membrane	$1,200 – $2,800
Each extra crack, same visit	Usually less than the first
Tie-rod hole	$75 – $150 each

Ranges drawn from published Toronto-area price guides (2026). These are general estimates, not quotes. Things that raise the price: tall walls, long or wide cracks, a finished basement, a previous failed patch, or heavy water flow.

When injection isn't the right fix

Block foundations: hollow cores don't hold the material. These are usually fixed from outside.
Structural cracks (horizontal, stair-step, bowing, offset): the cause needs to be fixed first.
Water not coming from the crack: leaks at the floor-wall joint (cove joint), through window wells, or from poor grading need a different repair. See leaking basement repair →

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Common questions

How long does crack injection take?

Usually 2–4 hours for one or two cracks, including setup. The material cures in a day or so. The contractor will tell you when it's safe to put finishes back over the wall.

Can a crack be injected while it's leaking?

Yes. Polyurethane is made for wet or actively leaking cracks: it reacts with water and expands to fill the crack. Epoxy needs a drier crack to bond well.

Does injection work on concrete block walls?

Generally no. Block walls are hollow, so injected material doesn't stay in the crack. Leaks in block foundations are usually fixed from outside, or managed with interior drainage.

Do I need to empty the basement?

Only the area along the crack. The contractor needs about a metre of clear space along the wall. If the wall is finished, a strip of drywall and insulation over the crack has to come off.

What if the crack leaks again?

Ask for the warranty in writing before you agree to the work. Many injection warranties cover re-treating the same crack at no charge for the life of the home or a fixed term.

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