Foundation Crack Repair · Ottawa
Foundation crack repair in Ottawa
Korvex Construction repairs cracked, leaking foundation walls from the outside across Ottawa, Kanata, Stittsville, Barrhaven, Nepean, Orleans, Manotick and Riverside South. We dig down along the wall, seal the crack, cover it with a waterproofing layer and fix the grading and downspouts that sent water there. Book a free on-site estimate and you get a written price.
- Foundation wall
- Waterproofing layer
- Parging
- Clear stone
- Finished grade
A foundation wall in section, from the parging down to the footing.
- Parging above gradeCut back and patched where the crack shows between the soil and the siding.Above the soil line
- Waterproofing layerCovers the sealed crack and a margin of wall on each side, on the buried part of the wall.Lapped at every seam
- Foundation wall, crack sealedCleaned along its full length and sealed from the outside.Sealed from outside
- Backfill and finished gradePlaced in layers, then shaped to fall away from the wall.Falls away from the wall
- FootingReached where the crack runs to the bottom of the wall.Bearing on firm ground
What goes wrong
Why foundation walls crack and leak in Ottawa
Most calls about foundation repair in Ottawa start the same way: a damp line down the basement wall after a thaw, or a crack you can see from the side yard. Almost every house has some cracks. Concrete shrinks as it cures, so a newly poured wall often has small vertical cracks, usually less than 1/8 of an inch wide and in the middle third of the wall. A crack like that is rarely a structural problem. It becomes a water problem when wet soil sits against it.
The ground here adds its own load. Leda clay, also called Champlain Sea clay, underlies most of the city and is sensitive to water and disturbance. Researchers who compiled Ottawa soil data report building damage from clay settlement in the region every year, and an older study they cite found that tall street trees lowered the groundwater at the front of houses compared with the back, which led to uneven settlement and cracked walls. Shrinkage of the clay as it dries is named as a concern in parts of the city.
Then there is winter. Water held in the soil against the wall expands when it freezes, and an Ottawa winter repeats that cycle many times. Backfill along a foundation is looser than the ground around it, so roof water from a short downspout or a bed sloped toward the house soaks straight down to the wall. A hairline crack that has stayed dry for years can start to leak in a spring with heavy snowmelt.
Block foundations behave differently from poured concrete. Cracks tend to follow the mortar joints in a step pattern, and water can travel through the hollow cores of the blocks, so the wet spot inside may be several blocks away from where water gets in outside. Some cracks point to movement in the wall itself: a long horizontal crack below grade, a wall that bows inward, a crack whose two faces no longer line up, or one that reopened after an earlier repair. Those are structural questions, and they come before any sealing.
An exterior repair deals with the water where it arrives. We open the ground along the wall, clean the crack, seal it from the outside and put a waterproofing layer over it, then backfill and shape the grade so roof and surface water move away from the house. The parging over the top is patched, and the patio, steps or garden that came up go back.
How we build it
How an exterior crack repair is done
The crack is repaired on the side the water comes from. Most of the job is the dig, the cleaning and what goes back against the wall; the seal itself is a small part of it.
- Read the crack first
Width, direction, whether the faces still line up, and whether it was repaired before. A sheared, horizontal or reopening crack is assessed before any sealing.
- Locates before the dig
Utility lines are marked through Ontario Dig Authority before any excavation, and private lines such as gas to a barbecue are found with you.
- Down past the crack
The trench goes below the lowest point of the crack, so the seal covers the crack from end to end.
- Clean, then seal
Soil and old coating come off the wall along the crack, so the seal and the membrane bond to sound concrete or block.
- Cover past the edges
The waterproofing layer runs past the crack on each side, because water travels along the wall before it finds the opening.
- Send the water away
Backfill is shaped to fall away from the house, and downspouts discharge onto grass at least four feet from the foundation, as City of Ottawa guidance asks.
What we build
Foundation crack repair: the work we take on
Cracks in poured concrete walls
A vertical or diagonal crack that lets water in at one spot. The ground is opened on the outside down past the bottom of the crack, the crack is cleaned and sealed along its length, and a waterproofing layer goes over it.
Stepped cracks in block foundations
Cracks that run along the mortar joints of a block wall. Water moves through the hollow blocks, so the dig is planned from where the water shows inside and where it can reach the wall outside.
Waterproofing over the repair
Once a crack is sealed, the buried wall around it is covered with a waterproofing layer. Where several cracks share one wall, the repair grows into exterior waterproofing of that wall.
Cracks at window wells, pipes and corners
Basement window openings, pipes through the wall and outside corners are where cracks often start. The well or the pipe is worked around, and the seal and the membrane are finished tight to it.
Parging above the soil line
Where a crack runs up past the ground, the parging over it is cut back and patched once the wall below is sealed, so the band along the foot of the house is whole again.
Grading and downspouts after the repair
Backfill goes in in layers and the finished ground falls away from the wall. Downspouts that emptied beside the crack are moved, and clear stone can replace soil or slabs along the house.
Patios, steps and beds over the crack
Slabs, pavers and plants above the crack are lifted and set aside before the dig, then put back on a compacted base once the wall is sealed and the trench is filled.
Related projects
Often part of the same job
“Vlad and his crew installed my patio in 2 days. Did excellent work and vlad answered any and all questions I asked. I highly recommend Korvex Development for any job you may require.”
Joe Ayoub · Patio installed
“Did awesome work! had them repair a leany fence and they were on time, cheap and super professional”
Josh Cohen-Collier · Leaning fence repaired
Related services
Often built together
FAQ
What homeowners ask about foundation crack repair
How is a foundation crack repaired from the outside?
The ground is dug out along the wall to below the bottom of the crack, the crack and the wall around it are cleaned, and the crack is sealed from the outside. A waterproofing layer goes over it, the trench is backfilled in layers, and the finished ground is shaped to fall away from the house. Korvex Construction does this work across Ottawa and its suburbs, and the free on-site estimate comes before any digging.
Is a crack in my foundation serious?
Most cracks carry no structural weight. A shrinkage crack in a poured wall is small, usually under 1/8 of an inch, vertical, and stays in the foundation wall. Home inspectors treat a few signs differently: a horizontal crack below grade running along the wall, a crack whose faces have sheared out of line, settlement cracks that add up to more than about 1/4 of an inch, and a crack that reopened after a repair. Any of those is assessed at the site visit before we propose sealing it.
Why do so many Ottawa foundations crack?
Concrete shrinks as it cures, so small cracks are common everywhere. Ottawa adds Leda clay, a marine clay under most of the city that is sensitive to water. Research on Ottawa soils links building damage to settlement when groundwater drops, including under tall street trees, and to shrinkage of the clay as it dries. Freezing water in the soil and roof water soaking the backfill beside the house do the rest.
Why repair the crack from outside instead of injecting it from inside?
Injection from the basement fills a single crack without digging, and for a dry, stable crack in poured concrete it can be enough. An outside repair fits when the leak comes with a drainage or waterproofing problem along the wall: it stops the water on the side it arrives from, and the grade and downspouts are fixed while the ground is open. Block walls also favour it, since water travels through the hollow blocks.
What about horizontal cracks or a wall that bows inward?
Those point to soil pressing on the wall, and sealing them does nothing to stop the movement. We point them out at the site visit, and before any exterior work is planned, a structural engineer assesses whether the wall is stable and what it needs. Once the wall has its engineer’s answer, the waterproofing, grading and drainage around it can follow.
Do I need a permit to repair a foundation crack in Ottawa?
Damp proofing of existing basements is on the City of Ottawa list of projects that need no building permit, and the work still has to meet the Ontario Building Code. Those exemptions do not apply to designated heritage buildings or homes in a Heritage District Overlay, where the City asks you to contact a Building Client Service Centre representative first. Structural repairs to the wall are a separate question, settled with the engineer.
When can a foundation crack be repaired?
Digging and backfilling need ground that is not frozen, and sealants and parging need temperatures above freezing to set, so on most Ottawa sites exterior crack repair runs from spring to fall. A wet spring can also hold the dig until the trench stays dry. If a crack is leaking in winter, book the site visit anyway: the crack gets looked at, and the work is scheduled with the written quote.
What happens at the estimate, and how is the repair priced?
We look at the crack inside and out, measure where it runs, check the grade, downspouts, window wells and anything built over the spot: a patio, steps, a deck or a garden. The price depends on how many cracks there are, how far down they go, what has to come up to reach them and how easily the side of the house can be reached. Korvex Construction gives you a written price after that visit, anywhere in Ottawa and the suburbs.
Book a free foundation crack estimate
Tell us what you want built and send a few photos. We come out, look at what sits under the job, and give you the scope and the price in writing.