What we see out in the field is three types of foundation walls that are being painted. One type are stone foundations. When we see stone foundations that are painted, 92% of them are peeling, which means that only 8% are not. The reason this is happening is because there is mortar in between each stone. These homes were built at least 80 to well over 100 years ago. The mortar in between the stone is decaying. When you put any type of paint on a foundation wall, it has to adhere to the wall. The mortar is old, brittle and moisture wants to come through. It does, and this causes the paint to peel.
The second type of foundation we see being painted are block foundations. These handle it a little better; about 90% of these are blistering or having paint problems, only 10% keep the paint intact. These are usually peeling because they are older structures, there is still mortar in between the blocks, and when you have mortar and it ages it does crumble. Paint needs to adhere to a surface.
The third style foundation wall are poured concrete foundations. These are a little bit better. In about 70% of these foundations we see peeling, which means about 30% of painted concrete foundations are fine. The reason is is usually peeling is because the damp proofing on the outside on the foundation is not really good anymore and the Lyme and minerals are being pushed inwards which is pushing the paint off.
People paint there foundations because it looks nicer. But, mostly it is because they have been told that this paint will waterproof foundation walls. On the can, you can actually read about the PSI (pounds per square inch) of water this paint can hold back, and it is not very much.
For waterproofing foundation walls, we recommend that you use a material that penetrates the concrete or mortar, so that it becomes part of the concrete. Then it grows microscopically in the pours of the concrete. When the water hits it, it expands. This material is a crystallized quartz material. I would not put any paint on any foundation walls.
For more information, contact A1 Foundation Crack Repair.