Installing a new fireplace or repairing an existing one? If so, you’ll need to understand how and where to use fireplace silicone sealant to seal parts properly and protect the space. In this article, we’ll break down exactly what fireplace sealant is and the practical tips you need to use it correctly.

What is a Fireplace Sealant?

Fireplace sealant is a term used to describe a kind of silicone caulk that manufacturers have designed to resist high temperatures without breaking down. An example of this kind of sealant is Hi-Temp 100% RTV Silicone Sealant. It’s a great solution for high-heat applications. This silicone rubber can withstand extremely high temperatures of up to 650°F.

What Are The Uses Of Fireplace Silicone?

There are several uses for fireplace silicone in new installation projects and repairs.

For starters, small cracks can appear in the tiles or stone materials used for the mantle and room-facing portions of a fireplace. You can seal these with a silicone caulk of similar color to prevent them from getting worse or causing further damage.

Sealing the flue is often done using silicone sealant. This is critical. If the flue is not properly sealed with fireplace sealant, hot smoke could leak into the indoor space, releasing toxic chemicals and creating a fire hazard.

Occasionally, ceramic tiles can fall off the facade of a fireplace. You can reattach these or glue on replacements using the same high-temperature silicone sealant. Professionals also regularly use it to fix cracks in the fire brick around a fireplace.

Fire brick, also known as refractory brick, is a brick designed to withstand high temperatures and used to line fireplaces, kilns, and other areas exposed to high temperatures. They are heat resistant and absorb the heat of fires to protect the rest of the home. It’s important to keep them in good repair.

Silicone will adhere to most clean surfaces, including glass, metal, plastics, fiberglass, wood, brick, and stone. This means that you can use it to attach and seal parts of the fireplace, such as the glass on the front-facing window or doors. Its heat-resistant properties and durability make it a great option for sealing around the gas lines as well.

How To Use Silicone Sealant For Fireplaces

You might think applying silicone is simple. Just take a caulking gun and pull the trigger. However, if you don’t follow the right set of steps, you could just be setting yourself up for another repair in a month or two.

Nobody enjoys that.

So, here are the detailed steps you can follow when using silicone sealant on fireplaces.

Step 1: Prepare The Surface

Whatever surface you are applying silicone to must be clean, dry, and free of any debris, dust, or old sealant. Surfaces can get pretty dirty over time, especially in the case of fireplaces. Wipe away old sealant, oils, and soot from any areas to which you are applying silicone in order to ensure the sealant goes down and forms a strong bond with the surface.

Step 2: Choose The Right Sealant

Typical silicone sealants will break down under high temperatures, potentially releasing hazardous chemicals. Thus, it’s important to choose the right high-temp silicone for your project.

Step 3: Cut The Nozzle

You will need a caulking gun and a tube of caulk to begin the application process. Look for guns that are high quality and designed with features to prevent dripping. This will save cleanup time later on.

Next, you’ll want to cut the nozzle on the tube of sealant. This will determine the size of the bead you will apply, so it’s going to vary depending on your needs. Cut at a 45-degree angle to create a smaller opening. Use a smaller angle and cut more of the nozzle off to get a larger opening.

Then, use the poke tool on your caulking gun to pierce the inner seal on the fireplace sealant.

Step 4: Apply The Sealant And Allow To Cure

Squeeze the trigger of the silicone sealant gun to start applying the silicone to the gap or mating surface. Try to use steady pressure instead of pushing too hard on the trigger. This will ensure a consistent, even application.

Wipe off any excess with a damp cloth. Depending on the purpose, you may also want to use a caulking spatula to smooth or flatten the sealant and press it into the gap.

Finally, you’ll need to allow the silicone to cure according to the manufacturer’s recommendations. Do not light the fireplace or do anything that could affect the curing silicone until this time is up.

For Any of Your Silicone Needs, Try Silicone Depot

At Silicone Depot, we know sealant. Whether you need high-temp sealant for a fireplace application or the right tools to spread and apply caulk, we have you covered. You’ll find our range of silicone sealants here.

Got questions? Our staff love to answer them. Contact us today by calling (812) 824-8000!