Please help. My home suffers from constant condensation from a damp sub-floor, My rear garden is very steep, as a result when it rains, the concrete sub-floor floods due to a high water table, then drains. However the concrete remains wet, and causes condensation to rise through the house. I intend to put a french drain at the rear of the house and am having a de-humidifier fitted. Buy is there any products out there that i could fit in place of an air brick that would suck dump air out or pump fresh air into the floor cavity to reduce the condensation