The basement of my backsplit consists of two concrete boxes offset
vertically about 3'. A concrete stairway connects the two boxes in
the middle (ie far from any exterior walls). After extensive rain, we
get a leak at the bottom of the stairs. Previous owners have tried a
bunch of quick fixes which I have now chipped/scrapped/sanded away.
The concrete in the whole floor is very soft and crumbles to sand on
the surface. The concrete in the leak area contains voids, and seems
to be discoloured brown and/or mixed with beach sand (no beaches
nearby!).

The lot has been graded away from the foundation and the downspouts
routed away from the house. Obviously, can't get at the exterior of
the leak area without tunneling.

Current plan is to chisel along the seam, apply silicate sealer and
hydraulic cement, then top coat with patching mix.

Any comments, suggestions, warnings?

TIA,
Chris

Chris wrote:
The basement of my backsplit consists of two concrete boxes offset
vertically about 3'. A concrete stairway connects the two boxes in
the middle (ie far from any exterior walls). After extensive rain, we
get a leak at the bottom of the stairs. Previous owners have tried a
bunch of quick fixes which I have now chipped/scrapped/sanded away.
The concrete in the whole floor is very soft and crumbles to sand on
the surface. The concrete in the leak area contains voids, and seems
to be discoloured brown and/or mixed with beach sand (no beaches
nearby!).

The lot has been graded away from the foundation and the downspouts
routed away from the house. Obviously, can't get at the exterior of
the leak area without tunneling.

Current plan is to chisel along the seam, apply silicate sealer and
hydraulic cement, then top coat with patching mix.

Any comments, suggestions, warnings?

TIA,
Chris

wrong approach. Don't do that! - email me. I'm in the epoxy business
and have had interior walls in my basement leak too.