We have a house built in 1979 Center Hall Colonial. The house is built into a hill so the front is at ground level and the back foundation is exposed.
The basement is dry, there is a cement slab floor and a 1" inch trench filled with gravel between it and the cement block wall which goes around the entire perimeter of the room.
We've been experiencing some Blistering of the cement block foundation walls. Bubbles of the cement block, but no actually water. This problem seems to be contained to the foundation of the house underground. ( but I've noticed some areas in the back of the house that is above ground with the same problem.
In addition Mold has begun to grow from the 1" trench up the wall.. not much but enough to be of concern.
1) Is this blistering a flaw in the cement block that was used by the builder? Or is this water seeping through the cement block wall?
2) Do I need to replace these blocks or can I address any and all exterior water issues outside the house and simply patch the damaged ones with cement?
3) After I kill the Mold with bleach, can I fill this 1" trench in with cement if I plan on finishing the basement so it doesn't grow back?
4) What exactly does this 1" Trench do? Is it for expansion/contraction of the foundation? Drainage? I've never seen any water in it but there is obviously moisture there since mold is growing up from it.
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