Chimney services
Breathable, never paintChimney waterproofing in Los Angeles
Brick drinks water. A breathable sealant lets the masonry dry out while stopping rain from soaking in, so a chimney stops spalling and leaking. The wrong sealant traps water and makes it worse.
Why waterproof a chimney at all
Because brick and mortar soak up water, and soaked masonry spalls, leaks and rusts the metal inside it. A breathable sealant stops the soaking without trapping what is already there.
A chimney has no roof over it and no wall behind the exposed part. It takes rain from every side. The brick pulls that water in, then a dry spell or a freeze pushes it back out, and the face flakes away. That is spalling, and once it starts it feeds itself.
Waterproofing breaks the cycle. The right product beads the rain off the surface while still letting vapour escape from inside, so the masonry can dry between storms.
The difference between sealants
A breathable siloxane sealer keeps rain out and lets the wall breathe. Paint and film sealers do the opposite, and they wreck a chimney.
People sometimes paint a chimney or coat it with a hardware store waterproofer to freshen it up. Those form a film. Water still gets in through cracks and the crown, but now it cannot get out, so it sits in the brick and spalls it from behind the coating.
We use a breathable siloxane or silane sealer made for masonry. It soaks in, so the brick keeps its look and still lets vapour pass. Done right it lasts years and is invisible.
How we waterproof a chimney
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Repair first
Cracked crowns, open joints and spalled brick get fixed first. Sealing over damage just locks the water in.
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Clean the masonry
The brick is cleaned so the sealer can soak in evenly, not sit on dirt or old coating.
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Apply breathable sealer
A siloxane sealer is applied to full coverage, so it penetrates and beads water while letting vapour escape.
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Check the crown and cap
The crown gets its own treatment and the cap is checked, since those are where most water enters from above.
When waterproofing is worth it
After tuckpointing, when the brick is spalling, and on any chimney near the coast.
Fresh mortar and repaired brick last far longer sealed. Spalling brick that is caught early can be stabilised before it needs replacing. And near the water, salt drives the whole cycle faster, so a coastal chimney benefits most.
It is prevention, not a repair on its own. We do it as the last step after any masonry work, so the chimney leaves sealed against the next wet winter.
Questions
Chimney waterproofing questions
- Can I just paint the chimney to seal it?
- No, and it causes harm. Paint and film sealers trap water inside the brick, which then spalls from behind the coating. A breathable masonry sealer is the only right choice.
- Will it change how the brick looks?
- No. A siloxane sealer soaks into the brick, so it dries clear and leaves the brick looking the same, just no longer drinking rain.
- How long does waterproofing last?
- A quality breathable sealer generally lasts several years before it needs redoing, longer on a sheltered stack, less on one that takes the full weather.
- Do I need repairs done first?
- If the crown is cracked or joints are open, yes. Sealing over damage locks water in. We repair first, then waterproof, so the seal actually protects sound masonry.
- What does waterproofing cost?
- It depends on the size of the chimney and whether repairs come first. On its own it is a modest job, and we quote it after a look at the masonry.
- Is it worth it if my chimney is fine?
- On a coastal or older chimney, yes, as prevention. It is cheaper to keep water out than to replace spalled brick and a rusted damper later.
Related
Work that goes with it
Water and caps
Service areas
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Keep the water out of your masonry
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818-348-1993Open every day, 8am to 8pm. Serving Los Angeles and the South Bay.
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