What it is, in plain English
Brick and mortar are porous — left bare, they absorb water. In Nebraska that absorbed water freezes and thaws dozens of times every winter, and each cycle pries the masonry apart a little more: spalling brick faces, crumbling mortar joints, a deteriorating crown. Waterproofing slows that process down. We apply a siloxane-based penetrating water repellent that soaks into the masonry and causes it to shed liquid water instead of drinking it in. Just as important, it's vapor-permeable — the chimney can still breathe, so moisture already inside the masonry can escape as vapor instead of being trapped. That breathability is what separates a proper masonry repellent from a film-forming sealer, which can trap moisture behind it and make spalling worse.
What's included
- Siloxane-based penetrating repellent — soaks in rather than coating the surface
- Vapor-permeable: sheds rain while letting the masonry breathe
- Helps slow freeze-thaw damage — spalling, cracking, mortar erosion
- Crown, cap, and flashing checked first — a repellent is not a leak fix
- Best done alongside a sweep or inspection, so we know the chimney's condition
- Starts at $500 — final quote depends on chimney size and access, confirmed before any work starts
Pricing
Waterproofing
A breathable siloxane water repellent for masonry chimneys — sheds rain, lets the brick breathe, and helps slow the freeze-thaw damage that wears masonry down. Starting price for a typical chimney; the final quote depends on size and access, and you'll have the exact number before any work starts.
Frequently asked
What does chimney waterproofing actually do?
It changes how the masonry handles water. Bare brick and mortar absorb rain; the siloxane repellent penetrates the surface and causes water to bead and run off instead. Less absorbed water means fewer freeze-thaw cycles working on the inside of the brick — which is the main way Nebraska weather breaks down a chimney over the years.
Why does "breathable" matter so much?
Masonry always carries some moisture — from the weather, from the ground, and from combustion inside the flue. A vapor-permeable siloxane repellent lets that moisture escape as vapor while blocking new liquid water from soaking in. A non-breathable coating (like some paint-on sealers) traps that moisture behind a film, where it freezes and can pop the faces off brick — the exact damage you were trying to prevent. That's why we only use a breathable product.
Will waterproofing fix my chimney leak?
Usually not on its own, and we'd rather tell you that up front. Active leaks most often come from the crown, the cap, or the flashing where the chimney meets the roof — not through the brick faces. That's why we check those first and address them before applying a repellent. Waterproofing is prevention for the masonry itself, not a patch for an existing leak path.
How long does an application last?
Manufacturers typically rate siloxane repellents at around ten years, but real life depends on the chimney's exposure — sun, wind-driven rain, and how weathered the surface was to begin with. We'll give you an honest read on your chimney rather than promise a number.
Does every chimney need this?
No. Masonry chimneys benefit the most — especially older brick that's showing white staining (efflorescence), soft mortar joints, or early spalling. A factory-built fireplace in a sided chase doesn't need masonry waterproofing at all; there, the chase cover and cap are what matter. If your chimney doesn't need it, we'll say so.
How much does it cost?
Waterproofing starts at $500 + tax, and the final price depends on the size of the chimney and how hard it is to access. We usually quote it while we're already there for a sweep or inspection — you'll have the exact number before any work starts, and there's no obligation to add it.