I have a hairline crack radiating from a corner of a window in the basement. This crack weeps water during very heavy rains. I have sealed the crack with urethane injection (Sika Crack Injection Kit), however there is an area of the crack that is covered by a stud of a wall running perpendicular to the basement wall. It seems that that part of the crack is still allowing a small amount of water to enter the basement.

Blue is the window, brown is the stud, black is the crack, green is the ground level outside the basement. The red outline is where the current crack seal was done. The top part of the crack is dry, and it looks like I have water coming in from just the part of the crack behind the stud.

Crack schematic diagram

The area of the crack is unfinished (the wall is there just to partition a workshop from the laundry/storage area), and I could remove the stud temporarily to gain access to the crack.

On the outside of the basement, there is a 2 feet wide strip without grass, so I have no problem digging there to reach the crack from the outside. The area that I did not seal is pretty shallow, so I'm wondering if it might be better to seal the crack from the outside (with the same urethane injection material)?

  • 1
    The real issue is that you need to change surface water drainage outside the house. Crack sealing is a good thing for other reasons, such as insects and gas transfer. Water however will always find its way thru if not in today’s storm it will with another. The long term solution is to change the outdoor drainage pattern.
    – Tyson
    Apr 3, 2018 at 14:42
  • I'm not sure that will help - the water table is pretty high in my area, and this happens only at this crack. There is actually another window 20' away from this one, which has a pretty big puddle right next to it (during the heavy rains) and it's not leaking at all. Also, there is another crack from the first window on the other side and that crack is bone dry
    – Eli Iser
    Apr 3, 2018 at 14:46
  • If the water table were this high, the crack would be pouring water 24/7. I’ve been here before, diverting drainage is the long by term solution. Even raising the bare area so that it slopes away from the foundation and planting grass or placing rock to cover it will do a world of good.
    – Tyson
    Apr 3, 2018 at 14:54
  • @Tyson this is a common response to water infiltration issues, but I don't buy it. It's like telling the Dutch "stop building dikes, lower the sea level instead". There will always be water in the ground. It might take a once-in-a-hundred-years rainstorm to saturate the ground, but it will happen. The building's envelope should be able to resist water infiltration, that includes sealing any cracks.
    – Eli Iser
    Apr 3, 2018 at 16:02
  • Common answer is correct! Good luck!
    – Tyson
    Apr 3, 2018 at 16:34


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.