Is it normal for the concrete covering my interior perimeter drain to be damp?

Question

I inherited an interior perimeter drain with a sump-pump as part of a basement waterproofing system when I purchased my new home two years ago.

Since then I have noticed that along the seam of the drain, where the concrete covering the drain system meets the basement slab, the concrete always appears to be darker in color than the rest of the floor and always has a damp feel to it.

The perimeter drain company says this is due to condensation. It would seem to me that if the drain is functioning properly then there should be little condensation occurring.

Does anyone have experience with these types of systems and know what I should be expecting as far as performance and dryness?

Answer 1

Ideally, the builder installed a vapor barrier under the whole slab including the drain but it sounds like they cut a hole in the barrier to dig the pit for the sump. Since concrete is fairly porous, it's probably wicking water from the ground. If it bothers you, try a sealer intended for concrete with your problem. Unfortunately, you can't tell how much pressure the water is under because it evaporates or runs into the sump. Although it shouldn't be much, it will still wreak havoc with surface coatings.