Rain leaks into crawlspace

[Tony]

My house sits on a stuccoed block wall which is on top of a concrete slab. (I use a mechanics creeper to get around in the crawlspace.) Anyway, for some reason the slab was made about 8" larger all the way around the house. (I'm not the first owner) When it rains little cracks between the slab and the mortar allow water to come in. I thought about using more mortar to form a beveled edge at the bottom of the block wall but pictured that developing little cracks also. I thought about silicone but didn't want to ruin the chance for the adhesion of anything else if the silicone didn't work.

I ended up "painting" the area where the cracks are with the basement wall waterproofing paint Lowes carries, it's called Lock Tite. It worked great for a couple weeks, then tiny cracks developed so I gave it another coat. That worked a couple weeks then it leaked again.

I'm thinking of silicone since it will remain flexible, and it should adhere to the waterproof paint well. To make things worse, the extra 8" of slab that sticks out isn't level and it makes the water run toward the block wall instead of away from it.

Any idea's before I try the silicone sealer?

[Lefty]

Don't use silicone. Use plain old black foundation tar instead. Two thin coats should suffice, and will remain pliable for many years to come. If you think there is a problem with standing water against the wall, then build it up to pitch away with mortar, let that cure for a week, and then tar.

HTH, Lefty

[norminn]

We used a latex stucco patch to repair defects on our stucco/block condo exterior. Warm climate. The stuff shrinks, but it certainly did the trick. We slapped together some concrete pavers and used the stucco patch as mortar to fill one hole left by removal of old metal cabinet. Cheap, no concrete to mix. For heavy appl., need several layers. It might work to build up a wedge so water runs down....sanded or not, paintable.

[Nate Nagel]

first, clean your gutters (seriously) if that doesn't help then I'd dig up the outside of the wall and coat that with some of that tar-like product intended for sealing outside basement walls, don't coat the inside unless the outside is dry, otherwise you're just trapping moisture in the block

nate

[Bob F]

I'd use polyurethane or polybutyl caulk rather than silicone. You can paint either.

[Tony]

Gutters are clean (well this time of year they take weekly cleaning since I'm in the woods). I have nothing to dig up. The slab is about 3 to 4 inches above grade level and all repairs will show.

[Tony]

I should have explained that all repairs will be seen. That's why I started with the waterproof paint... tinted to look OK with the stucco.

[Lefty]

In that case, I would spend few dollars more and make the repair with a hydralic cement instead of mortar.

HTH, Lefty

[Tony]

I've never used that. My other reasoning for the paint was that I could get it deep into tiny cracks, and I had hoped the paint would "give" with the expansion and contraction with temps. Evidently it didn't. I'll try a section with the hydraulic cement and see how long it lasts. Thanks.