Rising Damp Under Carpet

The common causes are a missing damp course or the deterioration of the damp course layer due to age.

Rising damp under carpet.

Fixing the damp proof membrane. Assuming that the damp proof membrane dpm under the concrete has failed in areas then yes you possibly would get the odd patch of dampness showing in the floor. This is less common in new buildings as damp proof membranes are required at the initial construction phase to prevent rising damp. It becomes a problem when the moisture levels are too high and water is transferred to the finishing layer above.

Rising damp also known as salt damp or salt attack is a natural phenomenon where salty ground moisture rises by capillary action up a brick or masonry structure such as a wall or a fireplace. It often happens to older buildings. To fix this problem would require isolating the source of the moisture problem and then taking the necessary steps to help the floor dry out. This can cause issues with mold and mildew especially if you have carpet or.

You also mentioned that there are vinyl tiles over the floor. The easiest problems to isolate and repair with damp floors are issues with above ground services such as leaking pipes. If your property is suffering from rising damp which then rises through to the surface of the concrete then this is a more complicated procedure to fix. Damp rising through concrete floor slabs is fairly common when a damp proof membrane has failed or was not installed before the floor was laid.