Portland's relentless rain is the number-one enemy of brick chimneys. A breathable water repellent keeps moisture out of the masonry — preventing spalling, cracking, and the expensive repairs that follow.
Brick and mortar are porous — they soak up water like a sponge. In Portland's wet climate, that moisture works its way into the masonry, then freezes and expands on cold nights. Over many cycles, this freeze-thaw action cracks mortar joints and causes the brick face to flake off, a process called spalling. Once spalling starts, it only accelerates, eventually leading to costly repairs or a full rebuild. Waterproofing stops the cycle before it begins.
This is the most important part: never seal a chimney with paint or a film-forming sealer. Those trap moisture inside the brick and make spalling worse. We use a vapor-permeable siloxane/silane water repellent designed for masonry. It penetrates the surface and blocks rain from soaking in, while still allowing any moisture already in the brick to escape as vapor. The result is dry, protected masonry that still breathes.
For a typical chimney in the Portland area, waterproofing runs between $300 and $800 depending on size and access. It's one of the highest-value maintenance steps you can take — a few hundred dollars now can prevent a multi-thousand-dollar rebuild later.
Waterproofing is the perfect finishing step after a crown rebuild or chimney rebuild to protect your new masonry for years.
Typically $300 to $800 for a standard chimney in the Portland area, depending on size and access. It's one of the most affordable ways to protect your masonry.
Most chimneys can be waterproofed in two to four hours. The masonry needs to be dry, so we schedule around the weather.
A vapor-permeable siloxane/silane water repellent made for masonry. Unlike paint or film sealers, it lets the brick breathe while blocking rain from soaking in.
A quality repellent lasts about 7 to 10 years. In Portland's heavy rain we recommend re-applying around that interval, or sooner if water starts soaking in again.
Get a free, no-obligation waterproofing estimate from a locally owned, fully insured chimney company.