Crack in basement wall leaking water problems show up after a big rain or a thaw, when the soil beside the house is soaked. The crack is the door. The cause is water that sits against the outside of the wall with nowhere else to go.
Check the drainage first. Our page on foundation cracks lists what to note before anyone comes out to look at the wall.
Quick summary
A wet crack means water is pressing on the wall from outside, usually after rain or melting snow has soaked the soil. Winnipeg homes sit on clay that swells and shrinks with water, and that movement can open cracks in a basement wall over the years. Fix the slope and downspouts first. Then have a pro check the crack in person.
Why does a foundation crack leak water after a thaw?
Snow piled against the house melts in spring. The City of Winnipeg tells homeowners to clear snow away from the foundation so that melt water does not seep in through the walls.
Rain does the same. If the ground slopes toward the house, water runs down to the wall, soaks the soil there and finds the crack.
Our clay soil makes it worse. A University of Manitoba study found that most Winnipeg homes sit on shallow footings over clay that swells when wet and shrinks as it dries. That movement caused cracks and leaks.
The same study surveyed Winnipeg houses and found about 94% had some damage. Most was minor.
Is foundation crack water seepage a sign the wall is moving?
It might be. A Saskatchewan concrete guide says cracks form as new concrete dries and shrinks, and a crack is not always a sign of bad work.
Change is what counts. The Government of Canada suggests you mark both ends of a crack with a pencil, then check back to see if it grows.
Take a dated photo each time with a tape measure beside the crack, so anyone who looks at it can see how it changed.
A crack that runs sideways or a wall that leans in is a different problem. Our wall bracing page explains what to look for.
What can you check outside before anyone comes?
Walk around the house after the next rain. Bring a phone. Look for places where water pools near the wall, or where a patio, deck or driveway now tilts back toward the house.
The City says sidewalks, patios, decks and driveways can settle over time and send water back to the house. It asks owners to build up the soil around the house so that rain and melt water flow away from the foundation.
Then find each downspout. City rules say each one needs an elbow and an extension or a concrete splash pad, placed far enough from the wall to stop seepage.
In late winter, shovel snow back from the walls. None of these steps needs a contractor.
What is the fix for a leaking basement wall crack?
A good pro asks why water reached the wall. The Saskatchewan guide says drainage around the foundation should be checked and corrected before a leaking crack is repaired.
For the crack itself, CAA Quebec describes two paths.
The first is a polyurethane injection from inside the basement. Liquid sealant fills the crack to its full depth, and it can go in while the crack is still wet. It stays a bit flexible, so it can hold a seal if the wall shifts slightly.
CAA Quebec notes that an inside repair usually costs less than outside work. The seal only lasts if the concrete is in good shape, and finished walls may need to come down first.
The second path is from outside. A crew digs a trench along the wall, seals the crack, and covers it with a waterproof membrane. CAA Quebec says that if the wall is unstable, only an outside membrane will stop the water.
Which one fits? We cannot tell from a photo, because someone has to see the wall, the crack and the yard in person. Our post on what changes the price of crack repair covers what goes into a quote.
When does a crack in a concrete basement wall leaking water need an expert?
Get help if the crack grows. The Government of Canada also lists cracks where water is seeping through and a large network of cracks as reasons to call a professional.
The Saskatchewan guide says to get professional advice on active cracks that widen over time.
Can I seal a leaking crack myself?
You can buy sealant at a hardware store. Still, the Government of Canada lists a crack where water is seeping through as a job for a professional. A pro can check whether the wall is moving before anything is sealed.
Why does my crack only leak in spring?
Spring brings melting snow and rain while the ground is still partly frozen. The City of Winnipeg links snow melt against the foundation to water seeping in through the walls. That is when the crack shows itself.
Does a leaking crack mean the concrete was poured badly?
It does not prove it. The Saskatchewan concrete guide says cracking is not always a sign of poor materials or poor work. The leak tells you water is reaching the wall.
Will a wet crack get worse in winter?
A crack can open and close as the seasons change, so track it with pencil marks and photos through the year. If the marks show it has grown, ask someone to look at it before the next thaw brings more water to the wall.
Ready to get the crack looked at?
Start with photos. Gather them, the dates on them, and a note on when the water shows up. Our crack repair guide lists what to note and the questions to ask any contractor before they give you a quote.