Damp Proofing
Damp proofing is the application of a moisture-resistant coating or membrane to a masonry surface — most commonly foundation walls, brick veneer, and chimneys — to slow water absorption and reduce efflorescence, spalling, and interior moisture problems. It is less robust than true waterproofing (which forms a continuous, pressure-rated barrier) but more cost-effective and better-matched to surfaces that need to breathe.
In depth
Silane and siloxane sealers are the gold standard for above-grade masonry damp proofing. They penetrate into the pores of brick and stone, chemically bond to the silicates inside, and repel water without forming a surface film — meaning the wall still breathes, water vapor can still escape from inside to outside, and the masonry's natural appearance is preserved. Applied after a thorough masonry cleaning, damp proofing can extend the life of a brick home by decades in a freeze-thaw climate and is one of the highest-ROI add-ons we recommend after a chimney or house wash.
How this shows up on our jobs
We offer silane-siloxane damp proofing as a post-cleaning add-on for brick chimneys and exposed foundation walls. In Madison winters, it is one of the best long-term investments a homeowner can make.
Services where this matters
Related terms
Crown Coat
A crown coat is the sloped mortar or cement cap that sits at the top of a masonry chimney, surrounding the flue tile(s). It is not the decorative cap piece (that's a chimney cap) — it is the poured or troweled waterproof seal that directs rainwater away from the flue and the chimney's interior bricks. A properly built crown coat is two inches thick at the flue, tapered outward to a drip edge overhanging the brick by about two inches, and cast from a waterproof mortar mix or a specialty elastomeric crown-coat product.
Efflorescence
Efflorescence is the white, chalky, powdery deposit that forms on the surface of brick, concrete, stone, stucco, and block masonry when water dissolves mineral salts inside the material and carries them to the surface. As the water evaporates, the salts are left behind as a crystalline residue. It is cosmetic — not structural — but it is frustratingly persistent because every rain cycle can push more salts to the surface.
Polymer Sealer
A polymer sealer is a protective coating applied to a cleaned and dried surface — glass, concrete, wood, metal, brick — that forms a long-molecule chain on the surface to repel water, dirt, and staining. In window cleaning, glass-specific polymer sealers (often silicon-dioxide based, sometimes called "glass coats" or "hydrophobic treatments") cause rain to bead and sheet off, which keeps windows cleaner 2-3x longer between professional cleanings. On concrete, acrylic or urethane sealers protect against oil, rust, and de-icing salt.
Weep Hole
A weep hole is a small, deliberately-placed opening at the bottom of a brick-veneer wall, window frame, or storefront glazing that lets trapped water drain out. On brick homes, weeps are typically vertical gaps in the mortar every four to six bricks along the bottom course; on vinyl and aluminum windows, they are the small slots in the bottom of the exterior frame. Without weep holes, water that gets behind the brick veneer or inside the window frame has no escape path and causes efflorescence, mold, rot, and interior leaks.