How to Build an In-Ground Fire Pit

How to Build an In-Ground Fire Pit

1. Overlaid Stone DIY Fire Pit

For an artistic-looking fire pit, instead of evenly shaped bricks, grab several unique rough rocks, and construct an overlaid stone fire pit. If your pieces are hearty enough you won’t need any cement for this pit either — but use common sense when building up your walls. Here are some additional tips to secure your structure:

  • If the stones do not feel secure, add in some non-flammable masonry adhesive, landscape adhesive or Liquid Nails.
  • For the center, line the bottom of your fire pit with one or two inches of sand.
  • The outside of your fire pit should be lined as well, and no grass or other yard matter should be within two feet of your pit.

Video

Create Air Holes

  • Leave gaps in the firebrick in four opposite points around the ring and then fill them with half bricks. These gaps are “draw holes” that feed air to the fire.
  • Prop up the half bricks until the mortar sets.
  • Check for level across the DIY fire pit and the vertical level of the bricks as you go.

DIY Mini Fire Pit

Evansville Living

Here's a true mini fire pit made using a flower pot to create the size and shape. Your fire pit will take the form of any large plastic container you choose, such as a flowerpot or urn.

For this DIY fire pit, Deb McDaniel at Evansville Living sprayed the inside of the container with non-stick cooking spray and poured in quickly setting concrete. Set one or more gel fuel canisters into the wet concrete to create the right-sized space (coat the canister with non-stick cooking spray for easy removal). Place rocks or beach glass into the still-wet, pliable concrete mix for a sparkling finishing touch. When the concrete dries, remove the container (gently break it apart if necessary or glide the concrete out of the container) for your unique fire pit.

What Stone Is Best for a DIY Fire Pit?

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Almost any type of rock can explode, particularly porous and moist rocks. When wet rocks become heated, the trapped water and air expand rapidly and violently shatter the rock, occasionally causing it to explode. 

River rocks, gravel, pumice, limestone, and sandstone are all examples of rocks that should be avoided when building a fire pit due to their porous nature and proclivity to retain water. 

Due to the density of hard rocks (such as slate, marble, or granite), they are less prone to absorb water and burst when exposed to heat. Additionally, fire-rated brick, poured concrete, lava rocks, and lava glass are all safe to use around and in your fire pit. 

This is one place where lava rocks can be used to ensure the safety of a fire pit. If your fire pit contains or is surrounded by rocks, exercise caution when igniting flames after it has rained. 

Wet rocks have a far greater chance of exploding than dry rocks. If you use your fire pit frequently, you may want to consider covering it during inclement weather to keep it dry and to keep yourself safe.

Step 5: Level Out Your Bottom Layer of Stones

Making sure your bottom layer of stones are flat and level is the most important part of the build. With out a level and flat base the rest of the stones stacked on top won’t be level or flat. Start by checking one stone with your level. Using your rubber mallet you can hit the stone in order to compact the dirt underneath it and get it to sit flat and level. After hitting it a few times, check the stone with the level again. Be sure to check both front to back and left to right with the level to make sure it isn’t leaning forward or backward or side to side. If you’re unable to get the stone level you may need to lift it up and either remove a high spot in the dirt underneath with the garden shovel, or add a small amount of dirt to raise it up. If you need to add dirt, just sprinkle it in loosely and allow the weight of the stone to compact it. Check it for level again and hit it with the rubber mallet as needed. Once you get one block level and flat continue the process around in a circle until you’ve leveled every stone.

Tools Materials

  • Brick hammer

    Brick hammer

  • Cold chisel

    Cold chisel

  • Spade

    Spade

  • Hoe

    Hoe

  • Metal rake

    Metal rake

  • Tamper

    Tamper

  • Level - 2 foot

    Level – 2 foot

  • Level - 4 foot

    Level – 4 foot

  • Mallet

    Mallet

  • Caulk gun

    Caulk gun

  • Pointed trowel

    Pointed trowel

  • Power grinder

    Power grinder

Step 2: Select Your Location and Lay Out Your Stones

Be sure when you’re selecting a location for your fire pit you are a good distance away from your house, there aren’t any low hanging tree branches above where the pit will be placed, and there is plenty of space around the fire pit for seating. Arrange your stones in a circular pattern. Be sure to get them as close and tight together as possible.

Finish Off the Top Lip

  • Mortar the brick caps.
  • Finish the pit with a matching “row-lock” cap using regular face brick set on edge.
  • You’ll need about 40 face bricks for this cap, which will:
    • Help protect the wall joints from rain
    • Keep sparks contained
    • Give you a nice ledge to warm your feet on.
  • Work with 10 to 12 bricks at a time.
  • Lay a 3/8-in. bed of mortar and lay the bricks on edge, then butter each brick on the outside edge as you go and press it into place.
    • Pro tip: We used brick, but you could use natural stone for a different look.

Repurposed Birdbath

Jeremy Poland / Getty Images

If you’ve grown tired of maintaining your birdbath or a costly water bill, a fire pit transformation may be just the thing you need. If your low-lying fountain is made of a fire-safe material like marble or terra cotta (concrete is not safe), disconnect all the water hookups, remove all plastic and flammable materials, and consider filling it with firewood. Or, if you want to get even fancier, switch out the water hoses for gas lines. You might want to consider hiring a professional for that part. It will instantly transform the use of your yard.

4. Above Ground DIY Fire Pit

There is no digging required for this DIY fire pit design! Select some handsome gravel for your foundation, spread it out to create your overall fire pit space, then stack your fire pit stones. The fire pit pictured was built with crushed concrete rock with some additional aesthetic details.

The pit’s stones ought to be more than heavy enough to be dry stacked — no need for adhesive or cement. Hang some outdoor lights above your fire pit to finish off your welcoming ambiance for backyard guests.

Fire Pit Parts: An Overview

Illustration by Gregory Nemec

A built-in fire pit is a glorified campfire, with sturdy walls of stone that help contain the flames and heat. That’s especially important in the parts of the country where there’s a risk of brush fires. So the first task in building any fire pit is checking local codes on open flames. The pit must be located far from overhanging trees, the house, and any other flammable structure.

To make building stone walls easier, you can use blocks made from cast concrete and molded to look like real stone (available at any home center). They’re flat on the top and bottom so they stack neatly, and some interlock for added strength. Glue them together with masonry adhesive. Choose a block with angled sides, meant to form curves when butted against each other. The optimal size for a fire pit is between 36 and 44 inches inside diameter. That will create enough room for a healthy fire but still keep gatherers close enough to chat.

As an added precaution, the fire pit should be lined with a thick steel ring like the ones used for park campfires. These protect the concrete in the blocks from the heat, which can cause them to dry out and break down prematurely.

A fire pit should sit low to the ground, with walls rising no more than a foot off the ground. But for stability, the base of the wall must be buried below ground in a hole lined with gravel, providing drainage and protecting against frost heaves in winter. The gravel also creates a level base for the stones to rest on. Most concrete blocks are about 4 inches high, so if the first course and a half sit underground, and there are two and a half courses above ground with a cap on top, you’ll end up with a foot-high wall—just right for resting your feet on while sitting in an outdoor chair.

FAQ About Building a Fire Pit

What do you put in the bottom of a fire pit?

You’ll want to start with a layer of sand at the bottom of the pit, and then top the sand with gravel, lava rocks, fire pit glass, paving stones or even bricks for your fire pit. Alternatively, you can simply use dirt.

How do you prepare the ground for a fire pit?

Clear away all grass and plant material. Excavate about 8 inches of soil, ensuring that the bottom of the pit is level and the soil is compact.

Can you build a fire pit on dirt?

Yes, you can build a fire pit on dirt. Make sure the dirt is compact and level.

What is the best base for a fire pit?

You have several options. Plain dirt is fine, but sand topped with gravel makes a more attractive base.

DIY Smokeless Fire Pit Conclusion

Regardless of the size of your garden or outdoor space, a fire pit is a perfect addition for outdoor gatherings. Whether you choose to make a DIY fire pit or buy one from an online store, you’ll find your family and friends will love hanging out this year at your new garden focal point.

Even if you have a small garden, we think this is a great investment and one that you can use at any time of the year. If you live in a cooler climate, it will help you spend a little more time outdoors without getting chilly in the colder months. Whichever fire pit you go for this year, we hope it makes a great addition to your garden setup.

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