Can you use spray foam insulation around a fireplace?

Sitting in front of a roaring fireplace on a chilly evening can be relaxing, romantic, and the perfect way to end a busy day. If you aren't careful, however, that very same roaring fireplace can cost you a great deal of expense. If a fireplace is not properly insulated, it's not just the burning logs or coals that will go up in smoke. Your money will, too.

Insulation and expense

A house that is poorly insulated is one that will end up costing the owner a great deal of expense. One way to keep costs down is to insulate the property with spray foam insulation. This is a polyurethane-based product comprised of isocyanate and resin. Very often sprayed into wall cavities, spray foam insulation dries and hardens quickly. It has a proven ability to keep a house warm and bills low.

Gaps and cold air

Spray foam insulation can be applied to a fireplace. It is very important, however, that certain steps are taken when using spray foam to insulate a fireplace. Cold air penetrates a home at those points where exposure to the elements are at their greatest. One of those points is the outside wall of the property, specifically where it backs onto the fireplace. Constant heating and cooling in this area creates cracking of brickwork. Left unchecked, heat will be lost through these gaps and cold air will enter the home.

Problems on the outside

Insulation of the outside bricks of a fireplace, as well as the exterior of the connecting chimney, is recommended as a way to combat heat loss. Spray foam insulation is not designed to be exposed to high heat. As the bricks on the outside of the fireplace do not reach high temperatures, however, the foam works very well at filling exterior cracks. Check for evidence of gaps from the base of the fireplace to the top of the chimney. Spray the cracked bricks with foam insulation until all are completely sealed.

Combustible concerns

Spray foam insulation can be used to fill certain cracks to fireplaces inside a house. It is a process not without hazards, however. Polyurethane is combustible. The application of spray foam insulation to areas of brickwork that are regularly exposed to open flames is not recommended. It is, however, permissible to use spray foam insulation on the outer bricks of a large fireplace. Providing the fireplace is of sufficient size, and the decorative bricks do not heat up, small cracks may be filled with spray foam.

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About the Author

Nick Redfern is the author of many books on UFOs, Bigfoot, the Loch Ness Monster, Hollywood scandal and much more. He has worked as a writer for more than two decades and has written for the Daily Express, Military Illustrated and Penthouse.