waterproofing basement concrete walls

Old 06-17-07, 09:51 AM
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Question waterproofing basement concrete walls

My 100+ year-old home in below sea level Slidell, LA has a small basement (14' X 20') with concrete walls up to ground level and brick walls from the concrete to the house sub-floor. When it rains, water seeps through the concrete walls in various places. Some are obvious small cracks which previous owners have attempted to seal/repair, etc to no avail.
I have collected all kinds of advertising for "waterproofing paint" at the big home centers, but in reading the material it can become quite involved, such as requiring "back chiseling" or "reverse chiseling", which in actuality is not easy.
I need help. Recomendations and directions.
Old 06-17-07, 01:05 PM
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This is one place where you will probably get many answers to your questions.
However, I am just going to give you a few facts and let you go from there.
Fact: You cannot stop water coming through a concrete wall from the inside.
Water travels through the soil under extreme pressure. Its called hydrostatic pressure. To keep water out you must dig down on the outside of the basement and put in a foundation drainage system, and also seal your concrete from the outside. Now, one other thing. If your concrete is over 50 or 60 years old, it is probably getting rotten. It is breaking down, and water is coming through the cracks inside of the concrete. These are cracks you cannot see. Now this is what is happening, and there are alot of solutions to seal the concrete from the outside. Good Luck
Old 06-17-07, 02:48 PM
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I agree in so far as you cannot stop water with any "sealers" or special paint etc. However it is not absolutely necessary to have to dig all around the outside, in fact you can do it from the inside. My basement has a system where the entire walls are covered with a special tough plastic/fiberglass mesh material that will not allow any water through. There is an approximately 6" deep trench dug all around the perimeter of the finished area with a plastic channel set in place. It's similar to gutters. The plastic on the walls directs all water into the channel. The floor is also raised with a material very similar to "Dri Core" except instead of the little rip off squares, the plastic part is in sheets and then 3/4" ply is laid on top of it. All water has nowhere to go other then in the drainage trench which leads to a sump and is then pumped into a "bubble pot" in the yard. This may sound like a lot, but nothing like digging around the entire perimeter from the outside to apply an exterior coating. However I should add that this will not reduce deterioration of the concrete. I am surprised that a 100+ year old house would even have a concrete foundation as granite or other stone and mortar would be more common for that era. Just whatever solution you decide on, it has to be absolute if you plan to finish the area. Moisture will bleed through sheetrock quickly and become a haven for mold and mildew. Good Luck!

Oh P.S. the above method is guaranteed for the life of the structure meaning as long as the house is standing. It must hold up fairly well

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