Is there a problem lurking in your smoke chamber? Most homeowners know that chimney cleaning is essential for minimizing fire and safety risks and prolonging the chimney and fireplace’s life span. However, there is one section of the chimney that is unfamiliar to most homeowners. It’s called the smoke chamber, and it turns out that it gets the least attention, but it is the most at risk of a chimney fire.
What is the smoke chamber?
The smoke chamber is the area just above the damper at the base of the flue. Its purpose is to direct the flow of smoke and gases up the flue where it exits the chimney into the atmosphere. The smoke chamber is built using a corbeled or block technique to prevent fumes from backing up into the living space.
The older corbeled method no longer meets current building code requirements due to an increased fire risk. Corbeling involves staggering the bricks like steps. The jagged edges increase the likelihood that the mortar joints will suffer accelerated deterioration due to its proximity to the heat and gases rising through the narrow chamber. The deterioration can cause gaps or voids that inhibit venting, increasing the risk of carbon monoxide poisoning. The accumulation of creosote in these areas can also increase fire risk and reduce its structural integrity.
On the other hand, smoke chambers in newer chimneys are built with a smooth surface. The absence of the jagged edges strengthens the mortar joints, increasing safety, efficiency, and performance.
Smoke chamber parging
The National Fire Protection Association (NFPA) recommends corbeled smoke chambers be parged to correct any deficiencies. Smoke chamber parging is a restorative process that smooths out the jagged surfaces filling in any cracks or gaps in the mortar joints with new mortar material. The restoration process reduces the risk of fire and carbon monoxide poisoning while increasing the fireplace’s performance. In cases with poor construction or extreme deterioration causing a structural issue, a cast in place restoration process may be recommended to repair the corbeling with a smooth, seamless surface. For minor damage when there are no structural issues, a sealant may be used to repair the gaps in the smoke chamber’s mortar joints.
Smoke chamber repair
It is recommended that homeowners have a professional chimney inspection to determine if their smoke chamber needs parging. If a review determines that parging is necessary, the chimney sweep will make the required repair to restore the smoke chamber to meet current local building codes. It will increase safety and will also improve fireplace efficiency, draft, and performance. Contact us to schedule your smoke chamber inspection today!