Building a Ground-Level Deck With a Fire Pit: A Complete Guide

Apply for a Permit

To build a fire pit or deck, you almost always need a permit from your local municipality's office or homeowners’ association. There are often restrictions on the size, material, and location of your fire pit, including its distance from your house.

Most fire pits must be at least 15 feet away from your home and 10 feet away from any trees, bushes, property lines, and sheds. You may also need to submit a detailed deck design to your permit board before approval.

Determine Your Deck Type, Size, and Location

There are many types of decks and deck materials. Take time to research the style and type you want and its future location in your yard. Consider the view and the direction of the sun during the times you'd use the deck most. Draw out a plan or two with rough measurements to get a feel of how your deck would fit best on your property.

Plan Your Fire Pit

Photo: Mila Naumova / Adobe Stock

With a customized fire pit, you can create the size, shape, and look you want. Most fire pits measure 36 to 44 inches wide, including the walls, to allow several people to sit by the fire without being too far from each other for conversation.

A fire pit height of 12 to 14 inches from the base of the walls to the ledge is ideal for guests to prop up their feet. Square or circular fire pits are ideal for building into a deck. One fire pit idea is to buy a fireproof steel insert that provides the outline of your fire pit, surrounded by brick, stone, or rock to encase the pit and protect the deck from heat.

As you plan your fire pit’s location, consider the direction that the wind typically travels. Your seating area shouldn’t be downwind of the firepit and you don’t want smoke blowing into your home's open windows. Consider building a test fire where you plan to have your pit to see how the location and size feels.

Mark Your Utility Lines

Before you dig post holes for your deck, call 811 or your local dig line. A local representative will come out to mark your utility lines so you know where to avoid digging.

Outline the Perimeter

Using wood stakes and mason line string, mark the perimeter of your deck. Adjust the markers and strings until they are level. With paint, mark where you’ll put your deck posts, ideally 3 to 6 inches from the inside of your line. When using 4x4 posts, your posts should be 4 to 6 feet apart. When using 6x6 posts, aim for 6 to 8 feet apart.

Level the Area

Next, dig out any shrubs or bushes that are in your deck’s area. Make sure the ground is relatively level before beginning your project. If it’s uneven, you’ll need to level your yard in that section before starting your build. 

Roll out weed-blocking fabric to prevent grass and greenery from growing under your deck. Overlap each layer by about six inches. Hold down the fabric with bricks or stones until the framing is built. You can lay down gravel on top of the fabric for better drainage under your deck, but it’s not required.

Dig Holes and Set Posts

With a post-hole digger or power auger, dig holes for your posts. Depending on the frost line in your area, you may need to dig anywhere from 12 to 48 inches deep. Insert your wood deck posts and ensure all the posts are level with each other using your mason line string and a line level. Mix and pour your concrete around the posts to secure them. Let the concrete cure according to the manufacturer’s instructions.

Build and Secure Your Rim Joists

Cut and then line up your pressure-treated 2x6 rim joists (the perimeter joists of your deck). Square the corners at 90-degree angles before screwing them in place with an angle bracket. Screw the joists into your posts, using an angle bracket for stability. Consider screwing each element in partially while you make sure the joists are level, then install the screws fully.

Install Floor Joists With a Cut-Out for a Fire Pit

Your floor joists are the crucial part of your deck that will hold up your deck boards, and they should run 12 to 24 inches apart across the entire width of the deck. Your floor joists should run opposite your deck boards.

Mark exactly where your fire pit will be, and cut your joists to allow for this space. A square or hexagon cut-out is easiest, even if you have a round fire pit. You can fill in the rest of the framed shape with lava rock for a seamless design.

Place your fire pit ring in the space as you work on cutting and installing the floor joists. Leave enough space for the stones or bricks that will surround the ring (put down a few layers of your wall for guidance as you build). Treat any cut ends around the fire pit with a wood preservative, and consider adding corner braces of 2x6 lumber around your fire pit opening for more stability. Remove your fire pit ring after building the joists around it.

Install the rest of the floor joists across the deck with screws and joist hangers, ensuring that your joists remain level as you install them. Add block joists between your floor joists for extra stability, especially if you’re building a large deck.

Add Lava Rock

Pour your bags of lava rock into the open space you created for your fire pit. This step creates support and a heat-resistant barrier between your fire pit and the deck. Level out the rock before adding the fire pit ring.

Insert Fire Pit Ring

Place your galvanized fire pit ring in the center of your fire pit cut-out on top of the lava rock, ensuring it’s level. Build two to three layers of your rock, stone, or brick fire pit wall around it. Having the wall there temporarily gives you a guideline as you secure your deck boards.

Install the Deck Boards

Place your deck boards crown up, running the opposite of your floor joists. Leave approximately 1/8 inch between boards for drainage. Secure each deck board to the joists with fasteners or deck screws. You can saw off any excess length after you secure your boards.

Construct Your Fire Pit Walls

Arrange your stone, brick, or pavers around your firepit to create the wall. Apply landscape block adhesive with a caulk gun to secure them in place.

Complete the Finishing Touches

Photo: Iriana Shiyan / Adobe Stock

Almost done! With a circular saw, cut off the excess of any deck boards that hang over the edge. Stain and seal your deck to ensure it holds up to weather and UV rays. Allow it to fully cure before adding your furniture, grill, firewood storage, and other fun outdoor accessories.