Even a chimney with a sound crown, good flashing and tight joints takes on water. Brick is porous, mortar more so, and a driving rain on the weather side of a chimney can soak several inches into the wall. In summer that water evaporates. In winter it freezes, expands and starts the slow process of spalling brick faces and pushing mortar out of joints.
Waterproofing slows that process down considerably. Asset Roofing & Chimney applies breathable, vapor-permeable masonry water repellents formulated for chimneys. Unlike paint or film-forming sealers, these penetrate the surface and repel liquid water while letting water vapor pass out, so the chimney does not trap moisture inside the wall. The treatment is invisible when dry and does not change the look of the brick.
Waterproofing is a preventive step, not a fix for a chimney that is already leaking. It belongs after repairs, when the crown, cap, flashing and joints are in good order, as a way to protect that work. It is particularly worthwhile for chimneys on exposed sites, older soft brick, and chimneys that have shown efflorescence or early spalling.
What chimney waterproofing from Asset includes
- Inspection to confirm the chimney is ready for waterproofing and does not need repair first
- Cleaning of efflorescence, soot and loose material from the masonry
- Minor repointing or crack sealing before application if needed
- Application of a breathable, vapor-permeable water repellent to all exposed masonry
- Treatment of the crown where a crown sealer is appropriate
- Protection of roofing, siding and landscaping during application
- Guidance on when reapplication will be due
