Introduction: How to Build an in Ground Fire Pit

By Braxton Wirthlin BraxtonWirthlin.com

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About: I’m a stay at home dad and woodworker, I have a youtube channel where I upload builds, tips, and how-to videos. More About Braxton Wirthlin »

I recently built an in ground fire pit in my backyard using landscaping flagstone and construction adhesive. With a total cost of around $80 and an afternoon of work I’ve got a fire pit that will last a very long time. Here’s how I did it!

Video

Tire Rim Tower

DIY Joy

As long as you have access to an angle grinder and can get your hands on two old truck or car tire rims that are the same size, you can make an industrial-looking fire pit. You won't need to weld the two edges together; the two can stack on top of the other. You'll need an angle grinder to cut out same-sized squares (or rectangles) from each rim, then turn one on top of the other, lining up the squares/rectangles. That should give you a large opening big enough to allow you to add firewood as needed. If you're going for more of an open fire option, you can also use only one tire rim and stack rocks and bricks stylishly around it. Tractor tire rims are giant and make an excellent option for a larger fire pit.

Strike the Joints

  • After you finish each section of face brick, use a jointer to smooth (“strike” or “tool”) the joints before the mortar dries too much.
  • The mortar is ready to strike if you press your finger into it and the indentation remains.
  • Striking gives the wall a uniform, polished look.
  • Remember to leave the draft holes open as you mortar each section of face brick and smooth out the finished joints.

Can You Make an Indoor DIY Fire Pit?

Most people choose to build a fire pit in their backyard as it is easier to clean up, but you may be wondering if it is possible to build your own fire pit indoors.

The good news is, you absolutely can. Indoor fire pits can be used to spruce up a sitting room or lounge area during the cold winter months.

Be aware, however, that building a fire pit indoors is a big project, and you will need to ensure the fire pit runs on gas, as wood-burning fires are not safe to have indoors.

If you absolutely must have a wood-burning fire indoors, it’s best to keep it in the fireplace rather than building a DIY indoor fire pit.

DIY BBQ Fire Pit

Red Door Home

Most backyard fire pits offer the charm of flames that can roast marshmallows. But Stacy at Red Door Home wanted a completely functional fire pit that can be used for cooking throughout the summer.

Two full-size grills rest atop a ring of retaining wall blocks, allowing Stacy to cook anything from steaks and kebabs to s'mores. Extending the use of the fire pit ensures that it can be used for more than just the summer season.

Pour a Sturdy Footing for Your Fire Pit Base: Stake the Forms

  • The concrete footing will create a stable base for the pit walls and keep the sides of your pit from cracking as the ground moves over time.
  • Stake the forms and mix up ten 80-lb. bags of concrete mix according to the manufacturer’s directions.
  • If you’re using hardboard forms, stake them so they’re nice and round.
  • If the forms aren’t quite level, raise one end and drive a screw through the stake.
  • If the forms aren’t completely round, reposition the stakes.

5. What Kind Of Rocks Explode In Fire?

Nearly any kind of rock has the potential to explode – especially if it is porous and wet. When wet rocks heat up, the trapped air and water expand very quickly and forcefully break the rock apart, sometimes causing it to explode. Some of the most common rocks that should be avoided in fire pit construction include sandstone, limestone, pumice, gravel, and river rocks because of their porous nature and tendency to hold water. Hard rocks like granite, marble, or slate are much denser, and therefore less likely to absorb water and explode when exposed to heat. Other rocks that are safe to use around and in your fire pit include fire-rate brick, lava glass, lava rocks, and poured concrete. This is one area where you can use lava rocks for fire pit safety. If you have rocks in or around your fire pit, be cautious when lighting fires after it has rained. Wet rocks are much more likely to explode than dry rocks. If you frequently use your fire pit, you may even consider covering your fire pit in adverse weather to keep it dry and keep yourself safer.

Frequently Asked Questions (FAQ) FAQ

Can You Build a DIY Fire Pit With Just $50?

While it is possible to build a fire pit with just $50, you may find this a bit difficult to accomplish if you don’t have bricks or cement blocks laying around. It is better to plan at least $100 to $150 when making a DIY fire pit.

Can You Build a DIY Gas Fire Pit?

You can build a DIY gas fire pit; however, you will need to buy the gas fire component as an insert. You can buy these inserts at hardware stores or online.

How Does a DIY Fire Pit Get Air?

Most DIY fire pits have a large enough hole to get air through the top. But for those who have made their firepit too tall, you can easily remove part of a bottom layer brick and add an air vent.

Is Making a DIY Fire Pit Cheap?

Making a DIY fire pit can be cheap when you already have several of the supplies lying around and you just want to burn wood. But when you want a gas fire pit, or you need to buy all the bricks, you will find a DIY fire pit will likely still cost you a couple of hundred dollars.

2. In-Ground DIY Fire Pit

The in-ground fire pit is becoming increasingly popular among DIY fire pit builders. Before digging into the ground, make sure you call 811, the federally mandated “Call Before You Dig Number.” Someone will come to mark the approximate location of any underground lines, pipes, and cables so you can dig safely. Once you dig your fire pit to the desired size, line the dirt walls with stones or brick. Follow these additional steps to get started:

  1. First, you will want to create a bottom layer of gravel, then cover it with the base of your fire pit — larger stones or bricks or an even covering such as quick drying cement.
  2. Consider adding a drain during this step to keep the pit from filling with rainwater and attracting mosquitoes. 
  3. Place your bottom layer of stones and make sure they are level so as the stones are stacked they will be flat. 
  4. Once the first layer is flat and level brush off any excess dirt to prepare for gluing the next layer. Apply some construction adhesive to the bottom of another block, turn it over, and stack on top of the first layer. Continue this process until your firepit reaches the top of your hole. 
  5. Backfill the edges and compact the dirt around the fire pit.
  6. Allow at least 24 hours for the construction adhesive to cure before starting a fire.

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.

How to Build a Fire Pit

1. Lay Out the Blocks

Photo by Kolin Smith
  • Dry-lay a ring of blocks on the fire pit site, placing them end to end until you have a perfect circle positioned where you want the finished pit to be. To adjust the size of the circle, you may need to cut a block. Hold the block over the gap it will fill, then mark it on the underside at the proper width.
  • Using a 3-inch cold chisel and a brick hammer, score the block on the mark, and continue the score all the way around the block.
  • Place the block on a hard surface (flat rocks or gravel). Hold the chisel in the score line, then hit it with the brick hammer until the block splits.
  • Clean up jagged edges with the tail of the brick hammer. Place the cut block into the ring.

2. Mark the Pit Location

Photo by Kolin Smith
  • Make sure all the joints between the blocks are tight and the front and back edges line up. Using a spade, mark a circle in the ground about an inch outside the perimeter of the ring.
  • Take note of how many stones make up the ring, then remove them and set them aside.
  • If the blocks you are using are interlocking, remove any tongues on the bottom of the first-course blocks so they will lie flat in the trench. Chip them off with the tail of a brick hammer.

3. Create a Level Trench for the Blocks

Photo by Kolin Smith
  • Using a spade, dig a straight-sided trench, 12 inches deep and as wide as one block, within the circle marked out on the ground. Then dig down 6 inches in the area encircled by the trench.
  • Lay the ring of blocks in the trench to see if all the pieces fit in a circle. If not, dig more to widen the trench. Remove blocks.

4. Fill the Trench

Photo by Kolin Smith
  • Fill the trench with 6 inches of 3/4-inch drainage gravel. Using a hand tamper, compact the gravel. If necessary, add more gravel to keep the trench level and even.
  • Always make sure the blocks line up perfectly in the front and back when you lay them out; a difference of 1 inch in the circle’s diameter could create a 3-inch gap between blocks.

5. Lay and Level the First Course

Photo by Kolin Smith
  • Place the first block in the ring. Using a 2-foot level, check that it sits level both side to side and front to back. Where the block is too high, tap it down with a rubber mallet. Where it’s too low, shim it slightly with a handful of patio base. Make sure this first block is perfectly level and positioned correctly in the trench before moving on.
  • Lay another block next to the first one. Butt the sides together tightly and line up the front and back edges. Using the first block as a reference, level the second block side to side and front to back.
  • Lay the rest of the blocks in the trench in this manner until the ring is complete and all the blocks you counted earlier are used. Make sure each block is perfectly leveled and lined up tight with its neighbor before moving on to the next one. (You may have to coax the last block into place with a mallet.) Using a 4-foot level, occasionally check level across the ring.
  • A small hit with a mallet can make a big adjustment; work slowly and carefully, block by block.

6. Assemble the Walls

Photo by Kolin Smith
  • Using a caulking gun, squeeze a zigzag bead of masonry adhesive across two adjacent blocks. Lay a block on top of the glue-covered pieces, centering it over the seam between the two. Make sure any interlocking parts on the blocks fit together well.
  • Continue until the second course is finished.

7. Fill the Pit

Photo by Kolin Smith
  • Fill the pit with 6 inches of gravel, which will help support the first two courses as they set up. Glue and lay the third and fourth courses, continuing to stagger the joints.
  • Insert the iron campfire ring into the circle. Adjust it to sit even with the top of the block wall. Fill any space between the ring and the block wall to the top with gravel.
  • Work quickly and only in a small area at one time; masonry adhesive sets up quickly.

8. Cap the Blocks

Photo by Kolin Smith
  • Loosely arrange the cap pieces on top of the pit walls. (If you are using natural stone, try to arrange the pieces together like a puzzle.) Lay one stone edge over the next and mark the upper stone where they meet. Also, roughly mark the stone for a 2-inch overhang on the outside of the circle and an inch on the inside. Using a brick hammer and a chisel, score the stone on those marks. On thick natural stone, use a grinder fitted with a diamond blade to score it more deeply.
  • Lay the stone on a hard surface. Split it by hitting a chisel in the score mark, or by tapping against the stone’s edge with the brick hammer until it breaks. Score and split each stone this way, moving around the circle in one direction until you’ve made a cap that fits together tightly.
  • If you’re using blocks, glue the pieces on top of the wall. If you’re using natural stone, combine the dry mortar with enough bonding additive—not water—to make a mix with a peanut-butter consistency.
  • Wet the wall with some bonding agent. Lay a large mound of mortar on two blocks. With the point of the trowel, make a groove across the mortar. Lay the capstone on top, push it down, then tap it with the rubber mallet to set and level it. Continue to lay the capstones in this manner until the wall is finished. Wait two days before lighting a fire.

16. Conclusion

you got this!

Your backyard fire pit is a great addition to get-togethers, parties, and family events. Some proper planning on how big to make your fire pit, the best rocks for inside your fire pit, and what kind of outdoor furniture to use around your fire pit, can help your fire pit add a lot of value to your home. Don’t underestimate how fire pit glass and fire pit glass rocks can impact the look of your outdoor fire pit. Now that you know what to put in the bottom of your fire pit you can enjoy the outdoors year-round and create memories that will last a lifetime. Don’t forget to add in some high-quality outdoor furniture from RST Brands to complete your outdoor landscaping look and environment. Like what you read? Share it with your family, friends. and colleagues.Updated on 04/21/2020 Original post from 10/8/2018 

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