Chimney Waterproofing

Brick and mortar are porous. They absorb water, and in our climate that absorbed water freezes, expands, and breaks the masonry apart from the inside — the freeze-thaw cycle that's responsible for most chimney deterioration in Western Pennsylvania. Waterproofing with a proper breathable sealer stops the absorption while still letting the masonry dry out.

Frank & Sons waterproofs chimneys using vapor-permeable sealers designed for masonry. This isn't a paint or a coating that traps moisture — it's a treatment that repels liquid water from outside while allowing water vapor to escape, which is exactly what aging brick needs.

When waterproofing helps

• After repointing or masonry repair, to protect the work.
• On older brick that's begun to absorb water.
• Where efflorescence keeps returning.
• As preventive care before winter.
• Any chimney that's never been sealed.

The right way to waterproof

The critical detail is breathability. A sealer that traps moisture inside the masonry does more harm than good — it can accelerate the very spalling it was meant to prevent. We use vapor-permeable products specifically formulated for chimney masonry, which repel liquid water from outside while letting trapped moisture escape.

We apply the sealer to clean, sound masonry — which is why waterproofing so often follows repointing or masonry repair. Sealing crumbling joints accomplishes nothing; sealing repaired, sound masonry protects it for years.