I looked at a couple of walls in a basement today. One of them is block and the mortar is deteriating in a few places and the customer wants it fixed.
The other wall is much worse. It looks like someone poured a new wall inside of it about 2 1/2 feet high to rienforce it at the bottom. Big pices (3″x3″) are falling out. Then above that there is another wall set back further that is fine. I should have brought my camera.
Anyway, is there a way I can wash this area to kill whatever is causing this? Treat it somehow? Then put a skimcoat over the area? Something that trowels pretty well and bridges the holes.
The walls aren’t going anywhere for now. It’s mostly an apperance thing. They aren’t that tall or that long. We are going to address some rainwater issues out side. The spots look pretty dry.
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Seems to me you need to determine why the wall is giving up before coming up with a repair. If it is a load of clay behind the wall and heavy rains caused its expansion to buckle the wall you are likely going to remove this material or otherwise correct the situation.
Even if the wall was not installed correctly to begin with it seems likely that removal of the old wall would be necessary. Could be tough if the wall carries weight. I don't want to discourage DIY solutions but from everything I read and understand such situations can be complicated.
Calling in a professional can save money in the long run. Try to find one familiar with your local conditions and soils. They will have sen similar situation before and have some experience in what worked, or possibly more important, what didn't.
That second case sounds like someone dug out the basement deeper. The short wall covers the excavation and the edge of the footing of the original wall.
spalling is cause by the freeze- thaw cycle. If no air entrainment was added to the mix, not much you can do.
How about if I spayed it with a TSP solution to kill it a bit. At least at the surface for a while. Then treat the areas with watered down concrete glue. That would penetrate into the concrete a bit to stabilize the area.
I've never done any concrete restoration, but I can try to do an upstanding job of it.
It does sound like the basement was dug out deeper in that area. It's under the back of the house. Makes sense. It also makes sense that the concrete is in much worse shape there.
If I do trowel on some mortar after the glue application is there a product that works well on vertical surfaces?
There's nothing to "kill". You're probably seeing some "mildew" that is actually efforescence (sp?) -- the leaching of lime out of the concrete and its subsequent recrystalization. When it recrystalizes it expands and splits the concrete surface off.
That word efflorescence is a tuff one for me. So before I skim coat the area is there some treatment to knock it off so my mortar doesn't get pushed off by it in the near future.
What is at the root of efflorescence? Is there some solution I can spray on it before my skim coat/ re-tucking?
"What is at the root of efflorescence?"Water is disolving salts and carrying it through the concrete and then when it evaporates leaves the mineral deposit behind.The water problems need to be fixed first.