My walls in my extension sitting room are covered in mould and mildew starting from the ground and going up wards on the walls... also my tiled floor gets very wet, as if dere is water comein up though the tiles!! Sum1 please help its being like this for a long time...

1. Where do you live?
2. What is the foundation under the extension and when was it built? (full basement with concrete walls, concrete slab, crawl space with concrete walls, concrete floor, dirt floor, etc)