Cedar Hills · Utah County
Repairing the Framed Chimney Chases of Cedar Hills
If your chimney is stone on the outside, it is worth knowing whether it is a stone chimney or a wooden box with stone on it. In Cedar Hills it is usually the second one.
This is not a criticism of how the houses were built. A framed chase with a listed metal flue inside is a perfectly sound way to build a chimney, and it is what most of this town has. But it fails in completely different ways from masonry, and diagnosing it as masonry wastes everybody's time.
What a chase actually is
A wood-framed enclosure, built up through the roof, containing a metal chimney pipe held off the framing by spacers. The outside is finished in siding, stucco or a stone veneer. The top is closed by a sheet metal chase cover with the pipe passing through it, sealed with a storm collar.
So the chimney is a piece of the house's carpentry, wrapped in weatherproofing. Every repair follows from that.
Where water gets in
The chase cover is first. Flat galvanized covers pond water in the center, rust through from the standing water, and drip inside the chase where nobody looks. The storm collar around the pipe is second: its sealant fails long before the metal does, and once it is open, water runs straight down the outside of the flue pipe into the chase.
Then the flashing where the chase meets the roof, then the veneer itself. Stone veneer is not waterproof. It is a finish over a drainage plane, and if the flashing at its base is missing or the weep path is blocked, water that gets behind the stone has nowhere to leave and sits against the framing.
The result of any of these is the same and it is worse than a masonry leak: wet structural framing inside a closed box, adjacent to a chimney. It can go on for years before a stain appears in the room.
What repair looks like
Replace the cover in stainless with a cross-break so water runs off and a drip edge so it leaves the sides. Re-collar and seal the penetration. Correct the flashing at roof level. Where framing has already been damaged, open the chase, replace the wet members and rebuild the weather barrier properly before the veneer goes back. That last one is not a small job, which is why the cover and collar are worth attending to long before they need it.
The masonry that is here
Some Cedar Hills homes do have genuine masonry, and those get the ordinary treatment: crown repair, repointing, and a vapor-permeable water repellent after the repair rather than instead of it. Establishing which type you have is the first five minutes of the visit.
Questions
Chimney Repair in Cedar Hills — common questions
How do I tell whether my chimney is masonry or a framed chase?
Look at the top. A masonry chimney has a concrete crown sloping away from the flue tile. A chase has a flat sheet metal cover with a round pipe coming through it and a collar around the pipe. From the ground, a chase also usually stops at a square corner rather than showing brick coursing all the way up.
There is rust staining running down our stone chimney. What causes that?
Almost always the chase cover on top. Galvanized covers hold water in the middle, rust from there, and the runoff carries the stain down the face of the veneer. The stain is cosmetic; the reason for it is not, because a cover that is rusting through is letting water into the framed chase behind the stone.
Can a leaking chase be repaired without taking the stone off?
Usually yes, if it is caught while the problem is still the cover, the collar or the flashing. Those are all accessible from the roof. Removing veneer only becomes necessary when water has been getting in long enough to damage the framing behind it, which is the argument for dealing with a rusting cover early.
Is a stone veneer chimney weaker than a real masonry one?
Not weaker, just different. A properly built chase with a listed metal chimney is a sound system and it has real advantages, including lighter weight and better draft from a warm interior flue. It simply has to be maintained as carpentry and sheet metal rather than as brickwork.
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Our other services here
Chimney Sweep Inspection Fireplace Repair Installation Gas Fireplace Caps & Dampers Dryer Vents All Cedar Hills services
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