Basement Wall Cracks
LESLIE: Next up, we’re going to take Kathryn in New Jersey who’s looking to repair some cinder blocks.
Kathy, what’s going on?
KATHRYN: Hi. Yes, I have cracks in my cinder block down in my basement.
TOM: 1950s house, Kathryn?
KATHRYN: Yes it is. (Leslie chuckles)
TOM: Good guess, huh Tom?
TOM: Yeah, it was a good year for cinders.
KATHRYN: Oh, was it? (chuckles)
KATHRYN: Well, they lasted me this long, so I have to agree with you, I guess.
TOM: What kind of cracks are they? Are they horizontal, vertical? Describe them to me and how big are they?
KATHRYN: Straight crack down the wall.
TOM: Straight horizontal or vertical?
KATHRYN: Is that horizontal or vertical?
TOM: Is it up and down or side to side?
KATHRYN: Vertical. Up and down.
TOM: Up and down. OK. And is it towards the corner of a wall? Does it stem from a window and work down?
KATHRYN: It’s right under – yes, it’s by a window.
TOM: Yeah, that’s typical because the window in the wall is obviously the weakest part, so that’s often where the cracks start. Now Kathryn, is this something that you think is fairly new or has it always been there and it’s just bugging you?
KATHRYN: No, it hasn’t always been there. It’s fairly new.
TOM: OK. Well, what I would do first is typically if you have movement in the foundation wall like that, generally – especially in a house that’s built as well as the homes were built in the 50s – typically, something has happened to the drainage conditions outside your house. If we’ve had a very, very wet year and if the downspouts are disconnected, if the gutters are filled, if the soil is sloping into the wall where you’re getting a lot of water around the house, what happens is that water goes down the outside along the foundation wall and gets under the footing and can cause some shifting. And so you want to be very careful to look at your drainage conditions on the outside of your house.
KATHRYN: Yes, well one thing I do have, the air conditioner has been put over on that side.
TOM: Well, that’s going to – the condensate drain from it’s going to be there and while that can be a lot of money – a lot of water, I should say – I don’t think that that’s contributing enough water to do this. I think it’s more of the overall drainage conditions that you want to take a look at.
KATHRYN: Yes. So I should look outside and see where there’s the dampness.
TOM: Yeah. Walk all the way around the outside. Look at the grading. Look at the drainage. Make sure the water is away from the wall.
Now as far as that crack is concerned, you can fill that crack with a urethane or a silicone caulk …
TOM: … and that’s just good to keep the drafts out, to keep any water from leaking through.
LESLIE: And you can have that caulk – it comes tinted to match the color of the cinder block so you would never even know it was there.
KATHRYN: Oh, OK. It’s urethane or …?
TOM: Or silicone.
KATHRYN: Or silicone.
KATHRYN: OK, fine. I’ll do that. And if there’s a little mold, should I wash that with just bleach?
TOM: Yeah. What’s the mold look like? Is it white and crusty?
KATHRYN: Like from a dampness.
TOM: Right, does it look like a powder; like a white powder; like a grayish-white powder? Yeah OK, that’s not mold. That’s why I asked you. That is evidence that water is getting through your walls, Kathryn. What you’re looking at …
LESLIE: It’s like a mineral deposit.
TOM: Exactly. Those are the mineral salt deposits and they’re left over when water leaks through the foundation walls and then evaporates into your basement. And if those conditions worsen, you’re going to be looking at floods.
KATHRYN: Fine. Well, I guess that answers my question then.
TOM: Kathryn, thanks so much for calling us at 1-888-MONEY-PIT, 888-666-3974.