How to determine if the basement leak is a foundation problem


I have a basement leak that happens every other year on average, after either a very heavy rainfall, or melting of a lot of snow. It occurs on only one wall of the basement, and I've detected water on the floor from opposite ends of that wall. This leads me to believe it's the foundation wall.

I had someone come in and open up the drywall from the inside a few years ago, and he said he couldn't find a leak. He then attributed the leak to an old window, and charged me to replace it, along with the drywall he ripped out. After another leak a few years later, I know it's not the window.

I've had spalling/cracking bricks on the outside of that wall replaced several years in a row, and there's a cement walkway right up against the entire wall, with no spacer in between. I also notice green mold outside around the basement windows, which are below ground level.

Does this sound like it could be the foundation leaking? If so, is this an expensive repair? The house is only 30 years old; what would cause this to be failing so soon?

Best Answer

It's nearly impossible for us to diagnose this without being there in person, but typically wet basements are caused by ground water--rather than a leaky window or the like.

The ground water needs to go somewhere. If the soil can't drain, it builds up pressure and looks for a way into your basement--either via the walls or, more often, where the wall connects to the footer at the floor.

Cheaper/easier things to try first:

  • Add/fix gutters and downspouts
  • run downspouts further away from house
  • properly slope the ground away from the foundation around the house.
  • install surface drains (such as a dry river bed)
  • have gutters/surface drains go to dry wells

More expensive/complex solutions:

  • Install internal footer french drains and a sump pump
  • dig down exterior to install exterior footer french drains and waterproof exterior

Fixing gutters and such is fairly inexpensive and a weekend project. Sloping the yard and surface drains are a bit more work, but still in the realm of DIY.

Installing footer drains and waterproofing the exterior below grade, however, is not a DIY project and will cost quite a bit.