Basment floor cracking & hydrostatic pressure

Observed a expansion crack with signs of moisture.

How would you report the cracking and moisture?

Anyone have any info on hydrostaic pressure?

Client wants to the finish the basement. I want to cover my a…


Is that really a crack or is it a seam?

Appears to be a newer home. Most likely no exterior sealant applied. Just poured the walls and back filled the next day. Recommend basement and foundation specialist evaluate. My two pennies…

Expansion crack or shrinkage crack? Is this picture of a wall or floor, I can’t tell based on photo. Also how old is house? Sump pump?


Yes the home is newer and was built in 2001. The moisture is at a seam.

The are 3 cracks at the poured foundation that where sealed with an epoxy.

Foundation has a 10 year warranty.


Would you really call out a structural engineer on the seam crack?



No not a structural engineer, just a basement and foundation specialist. They could recommend sealing or fixing techniques.

Here is what I would say…

Previous repairs of foundation wall. Staining and dampness noted. Repairs are required.

From what I know expoxy is the least favoured repair material. It is to ridgid and sometimes the repaired crack will reopen or new cracks will result. I believe you will find that the preferred method of repair is now polyurethane foam injection, it is pliable and is more of a gasket than a patch and does a much better job. Most expoxy injections are to seal cracks and leaks. Some purchasers think that because the foundation has been repaired in such a manner is a structural issue when in 99 percent of the cases its not a sign of structural failure of the foundation but shrinkage cracks, form ties, and seams.

That is a picture of the floor with the moisture meter. This is the picture of the wall that I previously posted.


My bad… I thought the original pic was a wall. Stuck me as odd being a seam there.


I appreciate the replies. It is hard to tell from a photos sometimes.

Just trying to help my client when he finishes his basement. The replies I recieved on both posts help.

I suggested that he may want to check with the owens corning system for finishing. The wall panels are removable. He can keep a watch on the wall cracks.

The cracks at the seams of the floor are a tough call. How can you predict if the water table rises and he gets moisture/water from hydrostatic pressure.

There is no sump. Maybe builder should of installed when the house was built.

He can seal the seam then it would just crak in other areas of the slab.

I would frame the 10 year warranty for the foundation. He may need it. I should keep a copy. I may need it.


Hydrostatic pressure will find another route to enter basment. To know if a sump was required when built he should check with the Town Building Department.

If this is an ongoing problem considering site drainage is good, then the weeping tiles may be clogged.

If you have a functioning drain tile below floor level, whether it is placed on the outside or inside the wall, you will not have hydrostatic pressure forcing water up through the floor. Picture this, water rises upwards, like filling a bathtub. When the water rises above the floor level, the water under the floor is trying to seek it’s own level, which creates hydrostatic pressure. The picture clearly indicates the exterior drain tile were either placed improperly, ie, to high, or are not functioning. I would recommend that your client notify his builder and have the problem corrected while it is still under warranty.