Damp floor cavity

[DNA]

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

 

[gregers]

how many air vents do you have,wouldve thought adding a few more and updating them all to the plastic type ones would be the first thing to do and the cheapest,have been lead to believe that the old terracotta type vents are about 6% efficient and the plastic one are about 65%.

 

[DNA]

Thanks, Have 12 air-bricks, all terracotta, did`t realise that they where so inefficient, that might the best option to change to the plastic, can`t be any worse than at present