Dark Areas Around Concrete Cracks, Seapage?

by lisa
(chicago)

Q. Our brand new home of only 2 years has a full basement with a concrete floor. It has cracks in it, but the other day we went downstairs and it looked like it was wet from seepage, but it wasn't wet there were darker areas in certain spots that weren't there before. What does this mean?

Thanks

A. The dark areas are moisture vapor that's traveling up through the porous concrete and out through the surface of the concrete floor. Because moisture will seek the path of least resistance, it usually shows up around cracks and the perimeter edges of concrete floors first.

The moisture in the ground under your concrete floor may not be able to escape through the drainage as easily as before because currently the ground outside your house is frozen and/or the end of the drainage pipe is clogged.

It's not uncommon to see darkening around concrete cracks when there is high humidity, very wet weather conditions and drainage issues under a concrete floor or around the outside of a foundation. (landscape settled next to foundation creating a pocket where water collects) The excess moisture has to go somewhere.

As long as it doesn't get worse, you probably don't have anything to worry about. The dark spots will go away as the ground unthaws.

If the darkening gets worse or you see standing water then you'll have to check the drainage system for a clog and the landscape around your house to make sure it pitches away from the foundation.