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Sealing basement walls

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Apr 13, 2013, 11:49 AM
Sealing basement walls
I have a concrete slab/block wall basement that I want to clean and seal good. The walls do get "wet"on the inside during heavy rain/snow melt, but alot of this will (hope) to be fixed soon from the outside. No free flowing water, just a clearly noticable dampness.

Can I put some type of sealant and possibly a paint coat on the block wall is this condition?

THANKS for an help.
Apr 13, 2013, 03:48 PM
Interior basement wall sealants are actually designed so that the wall must be damp for it to be applied and to work correctly. Get any of the dry powder, mix-up brands from a home store. Follow the simple directions - you'll note that you need to lightly most the walls with water for it to work so existing moisture is OK. The product uses the moisture within the wall to 'wick' the waterproofer deep into the pours of the block. Two coats about 24 hours apart are usually required for full coverage.

Interior waterproofers are usually the last resort after making whatever fixes you can from the outside. However, often digging down to the footers and waterproofing from the exterior is going to be an expensive and invasive option. Do check your gutters and downspouts to ensure that all are clear and that any runoff is directed well away from the house.

In the meantime, applying an interior waterproofer will stop minor dampness and clean the walls up.

Apr 17, 2013, 05:20 PM
I have a sort of related question.I also have a block wall basement.No water or leaks. Is it a good idea to paint it with a wall block paint.My fear is that if I ever get a leak won't the paint stop it and keep it inside the block?
Apr 17, 2013, 05:59 PM
paint companies think so. if the wall is open and you have the cash, it can't hurt. it is more likely to stay on than any regular paint if the walls get moist. if you put something else on the wall, you can't use waterproofing paint.

question is, if there is water back there, what's it going to do to you? if a little, it just attracts bugs. if more, it will try to find pinholes if you skimped on the paint and didn't put on that second coat. if a lot, it will probably make its own pinholes, and then more, as it leaches salts out of the block and the efflorescence pops off the paint.

so the big push needs to be outside. gutters, downspouts, sloping, yada yada is still the golden touch to drying a basement. when that fails, waterproofing will save the day. when that fails, a sump pump and effective drain line is the fallback.

if that fails, Drylok won't help you.

This message has been edited. Last edited by: swschrad,

sig: if this is a new economy, how come they still want my old-fashioned money?
Apr 17, 2013, 06:04 PM
You can 'paint' the walls with s interior sealer as I said in the post above. If you like the color, you could leave it at that. Or, you could do the sealer coats and then paint on top of it.

What you do not want to do is to paint the walls with ordinary paint unless you are 100% certain you will never need to waterproof. The paint will not act as a waterproofer - it will simply peel off in any areas that may get wet from outside. On top of that, once you paint you cannot waterproof from the inside without first removing all the paint.