How do I damp proof my basement or cellar?

There are several possible ways of damp proofing / tanking your cellar or basement and it is difficult to suggest the best way without actually seeing the cellar. Below are some suggestions that would be suitable in most cases.

FLOOR

(a) Paint the floor with 3 or 4 coats of a water based rubberised bitumen emulsion. Then put sand/cement screed on top (approx. thickness 50 mm). If the original floor is brick or flagstones, it would first be necessary to repair any decayed mortar joints.

(b) Alternatively put down a layer of sand then cover this with a layer of polyethylene damp proof membrane which is a plastic sheet obtainable from Delta Membranes. The sheet must be lapped up the walls and can be secured using flashing tape. Any joints in the plastic sheet should be made by holding approx. 10 cm of each piece of plastic together then folding them so that one of the pieces goes back on itself and the other lies on top. Then cover the plastic sheet with sand/cement screed