Applying Waterproofing Paint
Applying waterproofing paint in a crawl space can be extremely difficult, but is it worth it? The waterproofing paint manufacturing industry makes a great product. In many cases, the problem is not the waterproofing paint but how it is applied. The waterproofing paint has been tested to withstand water intrusion through cinder block walls and concrete at a certain psi when it is applied correctly.
Waterproofing Paint PSI
The PSI (Pounds per Inch) of most waterproofing paints are between 20 and 35. What this means is that the paint will resist water pushing through it (if properly applied) at the rated pounds per square inch. Here are the stats of a well reviewed waterproofing paint I found on the Home Depot website.
XYZ Brand 1 gal. Mold and Mildew-Proof Waterproofing White Oil Based Paint (Case of 2) ultra-low-odor formula designed to waterproof interior and exterior concrete. Waterproofing paint is guaranteed to stop up to 34 PSI of water pressure and prevents the growth of mold and mildew on the paint film for 5 years - guaranteed.
- Use on interior and exterior concrete and masonry surfaces either above or below grade
- Lifetime waterproof guarantee and unique 5-years mold and mildew-proof paint film guarantee
- Covers up to 100 sq. ft.
- Bright white, non-gritty finish applies easily to dry walls with brush or roller
- Prevents water seepage through cement, masonry and concrete block walls and basement floor slabs
- Not recommended for foot traffic
- Dries to the touch in 1 hour
- Clean up with mineral spirits
Waterproofing Paint Cost
Given the information above, the paint sells for $29 a gallon when purchased in a 5 gallon pale. So you invest $145 to cover 500 square feet for 1 coat and $290 for 2 coats and $435 for 3 coats which is most likely the appropriate amount to apply. Instead of apply paint, why not use a plastic vapor barrier over the block wall in the crawl space?
Here is a video to help explain more: