Dampproofing is usually a sprayed or rolled asphalt emulsion or cutback applied to the outside of foundation walls. It reduces capillary moisture from damp soil but has no crack-bridging ability and no resistance to hydrostatic head. Building codes allow it only where the water table is held at least 6 inches below the lowest floor; under hydrostatic pressure, true waterproofing is required.
Spec only calls for dampproofing on the north wall, but the geotech shows water at eight feet. That's a change order.
Also heard as
- damp-proofing
- dampproof coating
Do not mix it up with
- Fluid-applied membrane: A fluid-applied waterproofing membrane is thick, elastic and rated for water pressure; dampproofing is a thin moisture retarder.
Related terms
Hydrostatic pressure
Pressure from standing groundwater against a wall or slab, rising with the depth of water above that point.
Positive side
The face of a wall or slab that touches the water source, where waterproofing works best.
Fluid-applied membrane
A liquid waterproofing applied by roller, squeegee or spray that cures into a continuous rubbery film with no laps.
Drainage composite
A dimpled or ribbed plastic core with filter fabric that carries water down to drains instead of letting it sit on the membrane.