How To Build a Firepit From a Kit

Building a firepit can transform your backyard into a charming gathering space for friends and family. With the right materials and some basic DIY skills, you can create your own functional, long-lasting firepit in just a few hours. In this segment, This Old House expert mason Mark McCullough demonstrates how to construct a circular concrete firepit from a kit while providing step-by-step guidance.

Choosing the Right Location for Your Firepit

Before you begin building your firepit, you’ll need to select an appropriate location. Choose a spot at least 10 feet away from any structures, trees, or overhanging branches to minimize fire risks. Select an area with good drainage to avoid a waterlogged pit in the future.

Place the firepit close enough to your home for easy access but far enough to prevent smoke from entering the building. Most importantly, check your local building codes and homeowners association (HOA) rules regarding firepit placement and construction—local authorities may restrict firepit size, type, and location.

Materials and Tools Needed To Build a Firepit Using a Kit

To build a firepit using a kit, you’ll need to purchase and gather the right materials and tools:

Materials

• Construction adhesive: Use an adhesive low in volatile organic compounds (VOCs) to secure the blocks together.
• Crushed stone: Purchase just over 6 cubic feet of crushed stone for the foundation.
• Firepit kit: A firepit kit simplifies the construction process by providing all the required parts. This includes concrete blocks and a metal liner that can withstand heat.
• Lava rocks: You’ll need 5 cubic feet of lava rocks for the firepit’s interior.
• Paver base: You’ll need 2 cubic feet to create a smooth base layer.

Tools

• Caulk gun
• Hand tamper
• Level
• Rubber mallet
• Shovel
• Tarp
• Wheelbarrow

Preparing the Site for a Firepit

Proper site preparation will give you a stable and durable firepit. Skipping any of these steps can result in an uneven or unstable structure.

Step 1: Mark the Outline

Use the center ring from the kit and the first course of blocks to determine your firepit’s size. Mark the outline with spray paint or a garden hose.

Step 2: Remove Grass

Cut a circle a few inches wider than the outline and remove the top layer of grass. Set it aside on a tarp for later use. Removing the grass ensures the firepit will sit on a solid base.

Step 3: Excavate

Dig the hole about 8 inches deep and verify that the bottom is level to ensure your firepit’s stability. This allows room for the crushed stone and paver base.

Step 4: Compact the Soil

Use a hand tamper to create a solid base for your firepit. Compacting the soil prevents it from settling later, which could destabilize the firepit.

Building the Base of the Firepit

Constructing a strong base will give you a durable firepit. Follow these steps to build a base before you start laying blocks.

Step 1: Add Crushed Stone

Pour a layer of crushed stone into the hole and compact it with the hand tamper. This helps with drainage and stabilizing the firepit.

Step 2: Repeat Layers

Continue adding and compacting layers of crushed stone until the hole is almost filled. Each layer should be about 2 inches thick.

Step 3: Add Paver Base

Mix some crushed stone with stone dust and spread it over the top layer, raking it smooth and leveling it out. The paver base provides a smooth and stable surface for the firepit blocks.

Laying the Blocks

After preparing and building the base, you can start building your firepit. Follow the steps below for a sturdy and well-aligned pit.

Step 1: Place the Center Ring

Position the metal ring in the center of the base to use as a template. This will keep the structure circular and even.

Step 2: Set the First Block

Place the first block and check that it’s level both side-to-side and front-to-back. Use a rubber mallet to make any necessary adjustments before continuing.

Step 3: Complete the First Course

Continue placing blocks around the circle, checking that each one is level. Having an even first course helps the following layers to stay level.

Step 4: Add Subsequent Courses

Dry fit the next row of blocks, then apply construction adhesive underneath each block before setting it in place. This strengthens the structure by binding the blocks together.

Step 5: Repeat for the Third Course

Follow the same process for the final layer of blocks. Each layer adds height and more stability to the firepit.

Installing the Liner and Finishing Touches on Your Firepit

To complete your firepit, follow these final steps.

Step 1: Add Lava Rocks

Pour the lava rocks into the center of the pit, spreading them evenly. Lava rocks help with heat distribution for an evenly distributed fire.

Step 2: Patch the Lawn

Use the saved grass to fill any gaps around the firepit’s exterior. This restores the surrounding area and gives your firepit a more polished look.

Firepit Maintenance and Safety Tips

To keep your firepit functioning and your home safe, we suggest following these maintenance and safety tips:

• Allow the fire to burn out completely before leaving the area since embers can sometimes rekindle even if you think the fire is out.
• Clean out ashes regularly to prevent buildup, which can affect airflow.
• Keep a fire extinguisher or bucket of sand nearby when using your firepit.
• Inspect the blocks and liner regularly for signs of wear or damage, repairing or replacing pieces as needed.
• Never leave a fire unattended, as this could cause a fire in your backyard.