West Jordan · Salt Lake County
The Sheet of Steel Over Your West Jordan Chimney
If you own a house here built in the last forty years, the single most likely source of a chimney problem is a flat piece of galvanized steel you have never seen.
A chase cover is the lid over the top of a framed chimney chase. The builder version is typically thin galvanized sheet, cut flat, with a hole for the flue pipe and a storm collar sealed around it. It has one job and two design faults.
Most of West Jordan went up between the early eighties and the middle of the 2000s, which puts a great many original galvanized covers somewhere between twenty and forty years old. That is comfortably past the age at which a flat one starts letting go at the seams and the fastener holes.
Why the builder cover fails on schedule
Flat means water sits on it. Sitting water on galvanized steel finds the cut edges and the seams, where there is no coating, and rust starts there and spreads inward. Then the puddle drains through the rust holes and runs down inside the chase, onto the framing, the flue pipe and eventually the ceiling below. The second fault is the storm collar sealant, which is a bead of caulk in full sun and full freeze for twenty years and behaves accordingly.
The fix is not more caulk. A replacement in stainless, cut oversize with an overhanging drip edge and a cross break so it sheds instead of ponding, ends the cycle rather than resetting it. It costs more once and then stops being a line item.
What a cap does that the cover does not
The cap sits over the flue opening itself. It keeps rain and blowing snow out of the flue, and its mesh keeps birds and squirrels out. Along the Jordan River corridor there is enough wildlife pressure that an uncapped flue does eventually get occupied, and a nest in a flue is both a blockage and a fire load. A cap also breaks up downdrafts, which matters on the open west side of the valley where there is little to slow the wind before it reaches your roof.
Top-sealing dampers and the eight months you are not burning
A throat damper is a metal flap that never seals well and seals worse as it ages. A top-sealing damper is a lid at the top of the flue with a silicone gasket, held closed by a cable you operate from the firebox. Closed, it stops conditioned air leaving the house through the chimney and stops outside air, and inversion-season air on this side of the valley is not air you want, entering through the firebox.
Waterproofing masonry, carefully
Where there is real brick, the treatment has to be a vapor-permeable siloxane repellent, not a film-forming sealer. Masonry needs to breathe outward; a sealer that traps moisture inside the brick makes freeze-thaw spalling worse. We use the permeable kind and we do not apply it over joints that need repointing first.
Questions
Caps & Dampers in West Jordan — common questions
There is a rust stain running down the siding below our chimney. What is that?
Almost certainly the chase cover. Water ponds on the flat galvanized lid, rust starts at the cut edges, and the runoff carries the stain down the side. The stain is cosmetic; what it tells you about where the water is going is not.
We hear birds in the chimney every spring.
That is an uncapped or damaged flue. We remove what is there, then fit a cap with stainless mesh sized to keep birds and squirrels out while still passing flue gas. Removal has to come first, because capping over a nest just seals the blockage in.
Does a top-sealing damper replace the one in the fireplace?
It works alongside it. The original throat damper usually stays where it is; the top-sealing damper does the actual sealing because it has a gasket and it is at the cold end of the flue where the air loss happens.
Should we waterproof the brick before winter?
Only if the mortar joints and the crown are sound. Sealing over failed joints traps water where it is already getting in. We repair first and treat afterwards, and we use a breathable repellent rather than a surface film.
Also in West Jordan
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Chimney Sweep Inspection Chimney Repair Fireplace Repair Installation Gas Fireplace Dryer Vents All West Jordan services
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