Sealing Foundation Cracks So They Stay Sealed
Most poured concrete foundations crack — concrete shrinks as it cures, and soil and frost move it over time. Many cracks stay dry. The ones that leak let water in every time the soil around the house is wet. Foundation crack repair seals the crack through the full thickness of the wall, not just the surface.
We use polyurethane injection for leaking cracks — it expands and stays flexible — and epoxy injection when the crack also needs to be bonded back together. Both are done from inside the basement in most cases.
If water comes from somewhere other than a crack, see basement leak repair; for cracks caused by movement see structural repair.
Types of Foundation Cracks
| Crack | Usually means | What we do |
|---|---|---|
| Vertical hairline | Normal concrete shrinkage | Seal if it leaks |
| Vertical, wider or leaking | Shrinkage plus water pressure | Polyurethane injection |
| Diagonal | Uneven settling at a corner or opening | Injection; check for movement |
| Horizontal | Soil pressure bending the wall | Structural assessment, reinforcement |
| Stair-step (block walls) | Movement through mortar joints | Repointing or reinforcement |
| Floor cracks | Shrinkage or water pressure under the slab | Seal or tie into drainage |
Polyurethane vs Epoxy Injection
| Polyurethane injection | Epoxy injection | |
|---|---|---|
| Main job | Stop water | Bond the crack and stop water |
| Flexibility | Stays flexible as the wall moves | Rigid, very strong |
| Works on wet cracks | Yes — reacts with water | Needs a drier crack |
| Best for | Most leaking basement cracks | Cracks needing structural bonding |
| Typical price | $500 – $1,500 per crack | $500 – $1,500 per crack |
When a Crack Needs Repair
Water or damp lines
Any crack that seeps in rain or snowmelt.
White efflorescence
Water is moving through the crack.
Rust stains
Water reaching the rebar or tie rods.
Crack getting wider
Mark the ends and measure over time.
Horizontal or wide cracks
Need a structural check first.
Before finishing the basement
Seal cracks before drywall goes up.
How Crack Injection Works
Inspect
Crack type, width, length and whether it is active.
Prepare
Surface cleaned; injection ports set along the crack.
Seal the surface
Crack face sealed so the material goes into the wall.
Inject
Polyurethane or epoxy pumped in from the bottom up.
Cure & finish
Ports removed and surface tidied.
Warranty
Written warranty on the repaired crack.
Foundation Crack Repair Cost in Toronto
| Repair | Typical price |
|---|---|
| Basement wall crack injection (polyurethane or epoxy) | $500 – $1,500 per crack |
| Structural crack repair with reinforcement | $800 – $2,500 per crack |
| Concrete floor crack repair | $300 – $1,200 |
| Exterior crack repair (excavated) | Priced per linear foot dug ($100 – $250) |
| Inspection & quote | Free |
Approximate 2026 Toronto prices, not a quote.
Foundation Repair Work
Real Leaquida projects — no stock photos.
Related Services
Foundation Crack Types and What They Mean
Use this as a first guide. If you are unsure, send us a photo or book an inspection.
| Crack | What it usually means | Typical repair |
|---|---|---|
| Hairline vertical | Concrete shrinkage — common | Polyurethane injection if it leaks |
| Diagonal from a window or corner | Minor settlement or shrinkage | Injection; monitor width |
| Stair-step in block wall | Settlement or soil pressure | Assessment; often reinforcement |
| Horizontal | Soil or water pressure on the wall | Structural repair, not just injection |
| Wide or offset (over 6 mm) | Ongoing movement | Engineer assessment first |
| Tie-rod holes and honeycombing | Construction defects that leak | Plugging and injection |
| Basement floor cracks | Slab shrinkage or settling | Sealing; slab repair if heaving |
What Causes Foundation Cracks
Concrete shrinkage
Concrete loses water as it cures and shrinks, leaving hairline cracks.
Soil movement
Clay soil swells and shrinks with moisture and pushes on the wall.
Hydrostatic pressure
Water building up in the soil presses through any weak spot.
Frost
Frozen, saturated soil expands against the upper wall.
Settlement
Footings that settle unevenly crack the wall above them.
Tree roots and landscaping
Roots dry the soil unevenly; heavy landscaping adds load.
Basement Foundation Crack Repair, Step by Step
Inspect
We measure the crack, check for movement and confirm it is not structural.
Prepare
The crack is cleaned and injection ports are set along its length.
Seal the surface
The face of the crack is sealed so material goes into the wall, not out.
Inject
Polyurethane or epoxy is pumped in from the bottom up until it fills the full depth.
Finish
Ports are removed, the surface is cleaned and the repair is tested.
How to Keep Cracks From Coming Back
Manage roof water
Downspouts extended at least 1.8 m from the wall.
Keep the grade sloping away
Top up settled soil along the foundation.
Check the sump pump
A failed pump lets water pressure build again.
Mark and watch
Pencil the ends of any new hairline crack and check if it grows.
Foundation Crack Repair Questions
How much does foundation crack repair cost in Toronto?
Most basement wall cracks cost $500–$1,500 to inject. Structural cracks with reinforcement are $800–$2,500 per crack.
Is a cracked foundation serious?
Hairline vertical cracks are usually shrinkage. Horizontal, wide or growing cracks and bowing walls need a structural check.
Polyurethane or epoxy — which is better?
Polyurethane is best for stopping leaks because it stays flexible. Epoxy bonds the concrete when strength matters.
Can cracks be fixed from inside?
Yes, most poured concrete cracks are injected from inside. Some situations need exterior excavation.
How long does crack injection take?
Most cracks are done in one visit.
Will the crack come back?
A properly injected crack is sealed through the wall. If the wall keeps moving, the cause needs a structural fix.
Is there a warranty?
Yes, a written warranty on the repaired crack.
What is the most dangerous type of foundation crack?
Horizontal cracks and wide, offset cracks are the most serious because they point to pressure or movement. They need a structural assessment, not just injection.
Can I ignore hairline cracks?
A dry hairline crack is usually cosmetic. If it leaks, grows or shows efflorescence, have it sealed before it lets more water in.
Can you repair cracks in block or stone foundations?
Yes, but the method differs. Block and stone walls are usually sealed from outside or treated with interior drainage, because injection works best in poured concrete.
Will crack repair fix sticking doors?
Not on its own. Sticking doors usually mean the structure has moved; crack injection seals water out but does not move the wall back.
Get Your Crack Repaired
Send a photo or book a visit. We will tell you if the crack is cosmetic, leaking or structural and quote the repair.
Call now — Mon–Fri 7 AM – 4 PM(416) 992-5858Office: 58 Six Point Rd, Etobicoke, ON M8Z 2X2
Email: info@leaquida.ca
Licence No.: P94 4418977 (licensed contractor)