Smoke chamber repair specialists for Richmond Estates homes

What the smoke chamber does above the damper

A masonry fireplace has a wide firebox and a much narrower flue. The smoke chamber is the tapered space between them, rising from the throat and damper to the bottom of the flue. Smoke gathers there and is funneled upward.

Because it sits out of sight, the chamber is easy to forget until something falls onto the damper. Our pros treat it as its own part of the fireplace, with its own findings and its own line on the estimate.

• Collects smoke above the damper
• Narrows the passage toward the flue
• Carries the first flue tile at its top

Firebrick and clay linings inside a chamber

Some smoke chambers are lined. The code allows two linings, firebrick of 2 inches or more that meets ASTM C1261, set in medium duty refractory mortar, or vitrified clay of 5/8 inch or more that meets ASTM C315.

A lined chamber gets a different repair from a bare one. Loose or cracked lining units are reset or replaced and pointed with refractory mortar, and the surface is finished to match. We note the lining type during the inspection and plan the work around it.

Checking for loose or missing brick first

Before a chamber is coated, the masonry has to be sound. The data sheet we follow calls for the chamber to be checked for cracked, loose or missing bricks, failed mortar and obstructions that could prevent correct installation.

Loose units are reset in refractory mortar, missing ones are replaced, and badly broken sections are rebuilt. Those repairs go in before the finish coat, because a smooth coat laid over a moving brick will crack along the same line within a short time.

Reshaping a lopsided chamber

Some chambers lean hard on one side, have a pocket above the damper or narrow unevenly toward the flue. The chamber coating data sheet we follow describes using the material to reshape fireplace smoke chambers, as well as to smooth jagged edges and corbels.

Reshaping means building the coat thicker where the wall needs to come in and thinner where it is already close. We explain what the finished shape should look like, where the limits are and how the work affects curing time.

Heat and movement in chamber masonry

Every fire heats the chamber walls and every cool-down lets them shrink back. Over many years, that repeated movement works on mortar joints and on any earlier patch that was not made for heat.

A refractory coat is made to handle that exposure. Small fires after the repair, while the coat finishes curing, give it a good start. Hot, fast fires that push flames up past the damper are hard on any chamber, new or old, and we mention that at the walkthrough.