Fireplaces bring cozy warmth and cheer to any room, but bringing fire inside requires careful planning and safety measures. One important thing to include in your fireplace plans is a chimney that doesn’t leak.

Whether wood- or gas-burning, a well-sealed chimney is essential to the proper functioning of the entire fireplace. A leaky chimney can create serious health hazards, fire hazards, or make for a downright unpleasant evening battling a smokey, sputtering fire.

If you're installing or servicing fireplaces and chimneys, it’s important to make sure you have the right supplies for the job – including high-temperature silicone sealant.

What is Chimney Silicone Sealant?

Chimney caulk is the term usually used when talking about silicone sealant because caulk and silicone are both sealing products. They both often come in tubes and are applied using similar techniques. However, they are different.

Silicone caulk cures hard with a dry finish. It's ideal for sealing cracks and seams that don't need to flex and will remain dry. Silicone sealants have a shinier finish and cure into flexible, waterproof, UV-resistant seals that can last for over 15 years.

Fireplace Sealant for Keeping Out the Elements

A fireplace and chimney will either be built from brick or masonry or come prefabricated from the factory for installation. Both styles require exterior sealing to keep nature outside and interior sealing to prevent leaking fumes and house fires.

Sealing the Chimney's Exterior

Masonry fireplaces benefit greatly from exterior sealing. Masonry and bricks are porous, so they absorb water easily. When water freezes inside the air spaces in brick, rock, or cement, it expands the space. Years of repeated freezing and thawing will eventually cause the masonry to crack, deteriorate, and crumble.

For sealing a chimney’s exterior, you may want to consider using Hi-Temp RTV sealant. This sealant is resistant to the extreme temperature fluctuations and UV damage that chimneys are subject to.

Sealing Holes and Gaps During Chimney Installation and Maintenance

The best choice for this job is a tube of squeeze-out silicone. If you're doing many chimneys, you'll need a professional quality caulk gun to save your hands and create the perfect bead every time.

Because the silicone is completely waterproof and has great adhesion to many surfaces, it's an ideal product to fill in any gaps or openings that could create structural damage or housefires if not sealed properly.

Fireplace Sealant for Preventing Smoke and Heat Leaks

No one wants water damage or freezing air blowing inside, but those inconveniences pale when compared to carbon monoxide poisoning or a chimney fire. Those are all real risks of an unsealed fireplace – especially a gas-burning system.

Gas burning fireplaces are also more complex in terms of piping, fittings, and seals, but even wood-burning fireplaces usually have stainless steel liners inside the chimney. All of these gaps, seams, and connections need to be sealed with a high-quality silicone sealant that will stick to surfaces and seal well without cracking, peeling, or burning.

Simply lay a bead of high-heat silicone around the male side of the pipe, and slide the female end of the next one on top to create a solid seal. Do not smooth the bead of silicone sealant out flat before joining the pipes.

Silicone Depot's Chimney Sealants Will Stand Up to Years of Cheery Fires

There is no doubt that a fire in the fireplace brings an element of security and delight that satisfies an ancient part of our being. With Silicone Depot’s wide range of high-quality silicone sealants, you can ensure that every chimney you seal will serve its purpose, danger-free, for years to come!