North Tonawanda has a substantial stock of older housing near the canal and the river, much of it with stone or early block foundations that were built to breathe rather than to seal.
Those walls handle a certain amount of moisture by design. What they do not handle is the modern habit of finishing the basement and sealing the inside face.
What we deal with in North Tonawanda homes
Seepage through old foundation walls, mortar that has degraded from repeated freeze and thaw, and the damage that follows when a finished basement traps that moisture.
Frozen pipes in older homes with limited insulation are the winter counterpart, particularly along exterior walls.
Should I waterproof the inside of an old stone foundation?
Be careful. Sealing the inside face of a wall under pressure usually fails, and it stops the wall drying inward, which means the moisture stays in the masonry and freezes. Deal with the outside water first.
The mortar is crumbling between the stones.
That is freeze and thaw working from within, and it means the wall is genuinely wet rather than merely marked. Worth having it looked at as a structure question, not just a moisture one.