What a smoke chamber repair actually fixes

Open your damper and look up. The space between the damper and the bottom of the flue is the smoke chamber. Its job is to funnel a wide fire's smoke into a narrow flue without slowing it down. When it is built rough — stepped, corbelled brick with mortar squeezing out of every joint — the smoke tumbles instead of rising, and some of it comes back into your living room.

Signs yours needs attention

• Smoke rolls out of the top of the opening when you light a fire
• A smoky smell in the room even on days you have not burned
• Fast creosote build-up low in the chimney
• Visible stepped brick and mortar drips when you look up past the damper

What the repair involves

We parge the chamber — building the stepped surface back up into a smooth, symmetrical funnel with refractory material, so the walls slope evenly toward the flue. Done properly it restores the draft, cuts creosote deposits and brings the chamber back within the wall-thickness and shape requirements of the code.

Why the code figures matter

IRC Chapter 10 sets the smoke chamber's wall thickness and slope, the damper height above the opening, and how the flue is sized to the fireplace opening. Rebuild only the part that fell apart and you can end up with a chamber that looks tidy and still drafts badly. We build back to the figures — you can see them illustrated on our fireplace repairs page.