waterproofing basement walls

Penetrating damp is caused by water entering through defects in the structure of the house. The way to prevent and cure it is through a high standard of house maintenance. Keep the roof sound, and maintain the walls as described in this chapter. Repoint when it becomes necessary, and reined any defects in rendered walls. Seal any gaps between window and door frames and the walls with a proprietary sealant; keep gutters and downpipes clear of blockages; deal immediately with any plumbing mishaps that soak a wall; and apply an exterior grade si1icone based water repellent to porous walls. Damp in basements is common because they are below ground level and are surrounded by soil, in which damp is present. There is no practical way to eliminate damp from basement walls, but you can keep the damp at bay.

Prepare the walls by mixing a polythene sheet to them or by applying a damp-repellent liquid. Then fix bitumen lath to the walls with galvanized clout nails. Bitumen lath is a pitch-impregnated corrugated libre. The corrugations create channels on both sides of the material: thaw on the wall side form ventilation corridors in which the mist Can evaporate. Those on the room Side provide a receive plaster. Plasterboard can be used by do-it-yourselfers instead of plaster.  Another possibility is to build a partition wall clad with plasterboard close to but not touching the main wall of the basement, creating in effect a cavity wall, Normally the framework for a plasterboard partition is screwed to the wall, but for damp-proofing it should be fixed to the ceiling and floor, in the way outlined on page 126 for constructing a non-load bearing partition. It is a good idea to fit insulation blanket (of the kind used to line a loft) behind the plasterboard, so that the basement will be warm as well as dry. The floor of the basement will also need a damp proof membrane (such as clear polythene) to stop damp from rising through the floor. Overlap the membrane and the damp proof treatment on the walls.