Smoke Chamber Parging & HeatShield Cerfractory Foam

Improve Efficiency And Safety By Having Your Smoke Chamber Parged With HeatShield® Cerfractory Foam

The smoke chamber in your chimney plays a large part in encouraging proper draft — it helps funnel the hot air and gases from your firebox up into the narrower flue, where draft will carry it up and out. Its location in the system — right above the firebox — means the smoke chamber takes in a heavy share of heat, and carries an initial load of helping draft along, or curbing its optimum flow.

Commonly, smoke chambers have been built with bricks that are corbelled, or stepped, down to the smaller diameter of the flue (sometimes these bricks have holes). Unfortunately, these steps and voids halt the smooth flow of heated air from the firebox, and can contribute to poor draft and smoke issues.

The Benefits Of Parging A Smoke Chamber

The parging process involves using heat-resistant refractory mortar to smooth out the smoke chamber, leaving a seamless surface. It brings a number of benefits to the chimney system:

  • Performance – A parged smoke chamber encourages air flow, which makes your chimney function better. In some cases, it can even clear up issues you’re having with smoke coming into your living area.
  • Safety – The smoke chamber takes on a lot of heat, and if the masonry is damaged, that heat could transfer to nearby building materials. A parged smoke chamber adds an additional layer of heat protection. Refractory mortar is made to hold up to excessive heat, and it makes it so that less of that heat transfers directly to the masonry. Improved draft and minimized smoke usually means less creosote build-up, too, and less creosote means a safer, more functional chimney.

HeatShield® Refractory Foam: Another Great Smoke Chamber Restoration Option

Our techs also use HeatShield® Cerfractory Foam to increase the safety and efficiency of our clients’ smoke chambers. After application, the foam expands up to 50 percent and cures to a solid, sealed layer, making for a smooth and protected smoke chamber. Like all of HeatShield®’s products, it’s been tested to stand up to extreme temperatures, and carries a 20-year warranty!

Does My Smoke Chamber Need Work?

When Old Hat Chimney Service technicians inspect your chimney, we’ll note whether or not parging/HeatShield® Cerfractory Foam makes sense for your system. But a few different circumstances might indicate that your chimney could benefit from one of these improvements:

  • Draft issues – If your chimney isn’t drafting properly, it could be due to a lot of different issues — you might have debris blocking the flue, your home might be sealed so well that the fire isn’t getting enough oxygen, or your corbelled smoke chamber might be inhibiting draft. Our CSIA-certified techs can identify the source of draft issues during a thorough inspection.
  • Signs of water intrusion/efflorescence outside the smoke chamber – If you see white stains (efflorescence) or other discoloration on the outside of your chimney in the general area of the smoke chamber, it could indicate masonry damage.

Old Hat Chimney Service’s technicians can tell you whether parging or having HeatShield® Cerfractory Foam applied to your smoke chamber will help your chimney. Give us a call or click here to make an appointment!


You may be amazed to experience the difference a top-sealing damper can make. Could you benefit from this simple masonry restoration installation?

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