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RTI

Field & trade terms

Damp-proofing

Damp-proofing is the sprayed or troweled coating applied to the outside of a foundation wall below grade to keep soil moisture from wicking through the concrete or block. It resists dampness and vapor from ordinary damp ground, but it is not waterproofing — it isn't meant to hold back standing water or hydrostatic pressure. Which one a wall needs depends on the soil, water table and design; using damp-proofing where waterproofing was called for is a common and costly substitution.

Why it matters

Below-grade water problems are among the worst to fix because the wall is buried the moment backfill goes in. A thin, holidayed or wrong-product coating lets moisture into the wall and eventually the interior, and by then the only access is to excavate. It also has to work with the drainage — footing drains and granular backfill — not instead of it.

What an inspector looks at

The check is that the specified coating is applied continuously over the below-grade wall at the right thickness, with no thin spots, holidays or gaps at penetrations and the footing, and any protection board or drainage layer in place before backfill. It's confirmed the wall is clean and cured enough to take the coating first.

Because RTI closes items on a photo, damp-proofing is documented before backfill buries it for good — full, continuous coverage and the treatment at penetrations and the footing shown in frame, the only record once the soil goes back.

Knowing the term is step one. Proving it is the job.

RTI holds the submit button until every mandatory item is answered and the photos are attached, then chains the record so it can be proven untouched later.