Basement Floor Mystery

This is one I’ve never encountered before.
The basement floor is poured concrete and appears to be intact. Minor common cracks in some areas but nothing out of line to the norm.
If an item is left on the floor for a period of approximately 3 days a puddle of water appears under the item. Doesn’t matter what the item is(cardboard box, plastic pail, wood, etc.) moisture or a puddle will form.

Anybody have ideas as to what may cause this and a possible remedy?


Hi Allen,

it’s probably caused by capilliary action wicking up water to anything on the surface, could be caused by a poor concrete mix, maybe a floor sealer might help, but I’d talk to a damp-proofing contractor.



Sounds like they may have forgot to put down a moisture barrier (usually 6 mil poly) prior to pouring the basement slab.


Thanks guys. Sure seemed weird. Had never seen this before.

Allan’s in Canada. No moisture barrier required, just 4" of granular fill.

Four inches of granular fill doesn’t stop excessive water from moving through the concrete slab by capillary draw, etc.

I like the block of a barrier myself and believe it is the best practice.