Damp proofing
WHAT IS DAMP PROOFING?
Damp proofing is a coating, usually asphalt-based, that is either sprayed on or hand applied to the outside of the wall. Though less frequently recommended in modern residential construction, it is still an acceptable form of treatment in many situations. The drawbacks include an inability to seal larger cracks or holes left by form ties and the potential for damage by coarse or careless backfill. But with proper surface drainage, correctly installed foundation drains at the footing, and the absence of hydrostatic pressure to drive water infiltration, dampproofing can supply adequate and long-lasting protection for many crawl spaces and basements.
Waterproofing a foundation requires the same care as dampproofing in regard to surface treatment and drain pipe, but is much more exacting in the treatment of the wall itself. Obviously, if there is any doubt about whether or not dampproofing will do the job, it’s best to spend the extra time and money to waterproof, particularly for habitable space.
Of course the depth of the foundation wall and the use of the interior space will also determine the choice of methods. A 36-inch frost wall for an unheated crawlspace built on well-drained soil and employing a gravity drain is a good candidate for damp-proofing. The house next door with a 10-foot-high foundation wall and a finished basement might opt for a fully waterproofed foundation wall system.
