How to Seal a Fireplace Insert?

Sealing a fireplace insert is one of those small but important maintenance tasks that keeps your home efficient and safe. Whether you’re preventing heat loss, improving draft control, or just freshening up an old seal, the process is straightforward when done step by step. If your insert is looking worn around the edges or you’re noticing drafts, it’s probably time to reseal it. Here’s how to do it right.

Table of Contents

Materials & Tools

To get started, you’ll need high-temperature silicone or fireplace sealant, a caulking gun, a putty knife or scraper, gloves, a drop cloth or old towel, and a wire brush. If your insert has insulation or a rope gasket, make sure you have a replacement ready. Choose sealants rated for high heat, specifically those labeled for fireplace or stove use.

Step 1: Preparation

Start by making sure the fireplace insert is completely cool. Lay down a drop cloth to catch debris and wear gloves to protect your hands. If there’s ash or soot around the insert edges, clean it thoroughly using a dry brush or vacuum. This gives the new sealant a clean surface to stick to, which is key to long-lasting results.

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Step 2: Remove Old Sealant

Use your putty knife or scraper to gently remove the old, cracked sealant. If it flakes or crumbles, that’s a good sign it was due for replacement. For stubborn spots, a wire brush can help break it up. Clear out all the debris and make sure there’s no leftover residue. The cleaner the surface, the better the new seal will adhere.

Step 3: Apply New Sealant

Load your caulk gun with high-temperature sealant and carefully apply a thin, even bead around the insert where it meets the masonry or surrounding wall. Move slowly and apply steady pressure to keep the bead consistent. Don’t over-apply; more isn’t better here. Smooth it out gently with a gloved finger or caulking tool if needed.

Step 4: Let The Sealant Cure

Once applied, give the sealant time to cure. Follow the product’s label instructions for drying and curing times; most need at least 24 hours before the fireplace is used again. Keep the area dry and undisturbed during this time to let the seal set properly.

Step 5: Inspect The Seal (Check For Gaps)

After the sealant has cured, inspect your work. Look for any missed gaps or uneven sections. If you find any, go back and apply a touch-up bead to seal the spot. A tight, even seal keeps drafts out and prevents heat from escaping.

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Final Takeaways

Sealing your fireplace insert is a simple DIY job that can make a noticeable difference in comfort and efficiency. With just a bit of preparation and the right sealant, you can stop drafts, improve heat retention, and keep your fireplace insert functioning like it should. Do it carefully, and it won’t need to be done again for a long time.

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Josh Frank

Josh Frank is the driving force behind every fireplace project at Fireplace Delight. As our lead installation specialist, Josh brings over 15 years of experience in the industry, ensuring that each fireplace is not only functional but also a beautiful centerpiece for your home. His passion for creating safe, efficient, and stylish fireplaces is evident in every project he takes on. Whether it’s installing a new gas fireplace or transforming an outdated wood-burning unit, Josh’s expertise ensures the perfect balance of warmth and design. Click to Learn More About Josh