Need help to resolve block foundation problem.
I recently purchased a house that was built in 2002 in southwestern PA. The ground outside appears to be rock and shell. The basement walls were gray foundation block. The height of the basement is approximately 9 feet. Approximately 2 -2 1/2 feet is above ground level. On the one wall and three corners I noticed a white substance on the block. This white substance started at the bottom of walls/corners and would go up even past the ground level to top of basement wall.
First I cleaned and acid etched the walls and corners. Then I applied DryLok Masonry Waterproofer. I put approximately 4 coats of DryLok on the walls and corners. I was delighted at first, thinking I solved the problem. However, the problem resurfaced and this time looks tan/brown/yellow on the white DryLok walls.
I want to find out how to resolve this problem for good. Please advise me with what all I need to do. Please include everything outside and inside I need to do to fix this problem. Thank you. Look forward to your help.
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Replies
This is efflorescence, Minerals in the ground water are being left behind on the surface of the wall as the water wicks through the block and evaporates into the house. Your solution should have worked. but you may just need to water proof from the outside or put a perimeter drain and sump pump system under the basement slab to relieve the water pressure driving the moisture through the wall.
Perhaps the locations of the wet spots are also locations of downspouts outside. That wouldn't surprise me. If so, it would be worthwhile to deposit the downspout water as far away from the foundation as possible. Peter Yost has run several posts here at GBA on foundation drainage, which you might check out (Search) , in particular one on the Underground Roof. Your first step in any case is to try to prevent water accumulation to the base of the wall outside.
The salt source is often the mortar rather than salts in the soil or rock.
More info on Bill Rose's underground gutter idea can be found on this page:
https://www.greenbuildingadvisor.com/green-basics/stormwater-management
Look for the item in the sidebar with the headline, "Below Grade Flashing."
Peter Yost also wrote a GBA article on the concept:
https://www.greenbuildingadvisor.com/blogs/dept/green-communities/underground-roof
And here is Michael Maine's article on the topic:
https://www.greenbuildingadvisor.com/blogs/dept/building-science/ground-gutter