While there are a number of causes of basement leaks, by far, most wet basements result from leaking basement foundation cracks; fortunately, most cracks in a basement are easily and inexpensively repaired.
In this post we discuss several topics pertaining to cracks in poured concrete foundations – the most commonly constructed foundation type since the late 1970’s:
In this post:
What are typical basement / foundation cracks
Why basement cracks are repaired
How basement cracks are repaired
How long it takes to repair a foundation crack
Crack repairs that are more complicated
Typical basement / foundation cracks
Your basement foundation walls develop cracks for two main reasons (there are others):
1. Poured concrete shrinks as it cures, so the loss of water creates a void; and
2. The foundation settles due to settlement of the soil beneath the wall (the cause of most structural foundation cracks).
Shrinkage cracks are typically less than 1 mm wide and vertical while settlement cracks are wider and often on a diagonal
Why basement cracks are repaired
Homeowners will have cracks in their basement walls fixed for several reasons; here are the most common:
1. The foundation is leaking water into the basement, through a crack in the wall, and a basement leak repair is needed;
2. The basement is being finished and there is concern that a crack may leak sometime in the future;
3. The house is being sold and a home inspection is expected;
4. Ants and/or dirt is being washed into the basement through a crack; and
5. There is concern that the structural integrity of the foundation has been compromised.
Fortunately the vast majority of cracks in basements are not serious and can be easily repaired at low cost.
How basement cracks are repaired
The majority of cracks in your basement are shrinkage cracks; therefore, there is no structural concern to address during their repair. When dealing with shrinkage foundation cracks there are two ways to fix cracks in a basement wall:
1. Crack injection; and
2. Exterior crack repair.
Given the relatively low cost and the speed at which repairs can be done, the vast majority of foundation cracks are repaired by injection from inside the basement, a process whereby the crack is filled with resin; effectively completely eliminating the crack. Alternatively the foundation at the crack location is excavated and a flexible rubber patch is applied to the surface of the crack.
For more detail, read our post on how to fix cracks in foundation walls
Interested in finding out what these repairs cost? Follow this hyperlink for the cost to repair a foundation crack.
Interested in do-it-yourself basement foundation crack repair? Check out this article on fixing a foundation leak yourself.
How long does it take to fix a foundation crack?
One of the best things about fixing foundation cracks by injecting them is that a typical crack injection can be done within two hours; if a crack repair involves excavation, the job time will typically be six to eight hours.
Note: if you are excavating to repair a foundation crack, the lead time should be two to three weeks to allow for the marking of underground utilities which is legally required. It is in your interest to make sure that locates are obtained since not having them can potentially cost you alot of money.
Basement crack repairs that are more serious
When cracks in your basement walls are wide or far from being vertical, crack repair becomes structural. For more on this check out this article on crack stabilization. When dealing with structural cracks, resolving a basement leak becomes a secondary consideration and you need to have them looked at by someone with expertise.