Crumbling concrete basement walls

Old 04-06-16, 10:20 AM
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Crumbling concrete basement walls

The concrete walls in my unfinished basement are crumbling. I think the previous owner may have put DryLok or some similar product on them. But it appears that the crumbling is not only the paint, but also sometimes the concrete itself.

I had two basement waterproofing companies come out last year. One told me that I needed a $10,000 french drain system installed around the whole perimeter of the house. The other told me that there was no problem. The problem has only gotten worse since then.

I've been scraping the parts that are crumbling and bubbling with a paint scraper and vacuuming with a shop vac. But I'm wondering if there is a better solution.

Any suggestions about what to do to (1) cleaning the crumbling parts of the walls and removing the DryLok and (2) treating the concrete to stop further deterioration?

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Old 04-06-16, 10:58 AM
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Welcome to the forums.

What's going on outside to keep water away from the walls in the first place? Gutters, downspout extensions and grading, to name a few things.

As to the inside, I'd hit it with a wire brush and the shop vac.
Old 04-06-16, 11:12 AM
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I wouldn't touch the inside until the outside has been sealed properly. Post some wide angled pics of the outside wall. Besides looking at the gutters & downspouts, look at the pitch & look for hairline cracks in the foundation.
Old 04-06-16, 03:34 PM
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Putting drylock on the interior side of basement walls can often weaken the mortar just like your photos. Its usually a bad idea. Sandblasting, shot blasting or just scraping it (maybe with the help of a rotary chipping hammer and wide chisel attachment) are good options. A drill and wire brush would be pretty dusty.

Concrete is always best waterproofed from the outside.

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