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Concrete Fire Pit



This modern outdoor concrete fire pit can be built over a single weekend and is a great centerpiece for outdoor entertaining. This is not a difficult project but is time consuming and labor intensive. Concrete fireplaces and fire pits should be constructed carefully. When exposed directly to high amounts of heat the moisture trapped inside concrete can expand, causing the concrete to crack and in extreme situations explode. I lined the inside of the fire pit with fire brick and filled the bottom with lava rock to ensure that the majority of the heat from the fireplace is not coming in direct contact with the concrete. I built this fire pit in southern California so I didn’t have to worry about putting in footings that go below the frost line. If you are building this pit in a cold climate, I would recommend putting a sonotube footing under each of the four corners.

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  • More Information, Tools, & Materials

    • Project Information

    • Tools Used

    • Materials Used

      • 2X4S AND 2X6S [HELD TOGETHER WITH 2.5" DECK SCREW TO MAKE THE PANELS FOR THE FORMWORK]
      • 6" L-BRACKETS [TO JOIN THE PANELS AT THE CORNERS]
      • QUIKRETE 5000 CONCRETE MIX [20-25 BAGS]
      • FIRE BRICKS [I USED FIRE BRICKS FROM A LOCAL MASONRY SUPPLY YARD. FIRE BRICKS ARE HEAT RESISTANT AND WILL PROTECT THE CONCRETE FROM CRACKING.]
      • MORTAR [I MIXED MY OWN MORTAR FROM A COMBINATION OF PORTLAND CEMENT, MORTAR CLAY, AND SAND. FOLLOW THE DIRECTIONS THAT COME ON THE MORTAR CLAY BAG.]
      • REBAR [I BOUGHT PRECUT REBAR IN 12” AND 36” SECTIONS. I SHOULD HAVE PURCHASED 18” LONG SECTIONS FOR THE VERTICALS.]
      • GRAVEL [I USED ABOUT 7 BAGS OF QUIKRETE ¾” GRAVEL FOR THE FOUNDATION LAYER.]
      • LAVA ROCK [I USED TWO 5 GALLON BUCKETS FULL OF LAVA ROCK PURCHASED FROM THE MASONRY SUPPLY YARD. THE LAVA ROCK IS HEAT RESISTANT AND WON'T CRACK OR SHATTER.]
  1. Project Steps

    1. Step: 1

      Large 183a1a23 a395 426d be52 6b59ae5d0558

      Assemble the panels. I used 2.5” deck screws and 15” long pieces of 2x4 to make the 4 large panels for the outer frame

    2. Step: 2

      Large f3b0748f 1af8 4d93 a954 c69a0cd591df

      Make the inner frame. The inner frame is made from 2 panels that are 23” long and 2 panels that are 20” long. Make sure to put the L-brackets on the inside corners of the frame since the outside ones will be buried in concrete.

    3. Step: 3

      Large a9d5dd3c 3492 4f18 95d2 064f85adb7b4

      Place the frame and mark the hole. Place the frame in the desired location and mark about 6inches around the outside perimeter.

    4. Step: 4

      Large 3e7ffd50 154d 4b26 aa4c 415f82d3d005

      Start digging. Since I am built this fireplace in southern California I didn’t have to worry about putting in footing below the frost line. If you are building in a cold climate I recommend putting in footings that go beneath the frost line under each corner. I dug about 8 inches down. I used a stamper to flatten and compact the soil at the bottom of the hole.

    5. Step: 5

      Large 2060ca04 615a 4adf 9769 f00526e0de0e

      Spread some gravel. I spread about 3.5” of Quikrete ¾” gravel in the bottom of the hole and raked it as level as possible before stamping it down.

    6. Step: 6

      Large 1efbee22 ce7d 4eab 8c68 6bf3a673cf4e

      Place the formwork. I placed the frames into position and measured the distance between the inner frame and outer frame to make sure the inner frame is properly centered.

    7. Step: 7

      Large 47b59cce f7ef 4e18 b5cf 002bbad59b4e

      Secure and level the formwork. Once the frames are in the right position I used some scrap 2x3s to and deck screws to lock them into place. I then used a 6 foot level to make sure that the formwork was level. I used a rubber mallet to knock down the high corners to make it more level.

    8. Step: 8

      Large e2102f43 97b5 44ac ac96 ee8a08ea5106

      Place the Rebar. I drove the rebar through the gravel and into the ground. I should have used longer rebar instead of the short 12” long vertical pieces. I then wired 3’ long pieces horizontally about 2” from the bottom of the hole.

    9. Step: 9

      Large 4ff534b8 2fc2 438f 8bf0 90b185661fa3

      Pour the first layer of concrete. I started with a 3.5” deep pour of concrete that would serve as the foundation of the fire pit. I mixed the Quikrete 5000 in a wheelbarrow and shoveled it into place. Renting a mixer would have made this a lot easier but I enjoyed the exercise. Let the concrete cure at least 20 hours before laying the brick.

    10. Step: 10

      Large 5c12a21d b606 453a a80f 0b335cd76bfc

      Lay the brick. Once the concrete has cured at least 20 hours get ready to lay the fire brick. I mixed the mortar per the instruction on the bag of mortar clay. I started with a thick base of mortar about ½” around the inner perimeter of the formwork I then placed the bricks one at a time. I spread mortar on the side of the bricks before place them so that they would stick together.

    11. Step: 11

      Large 2a977325 252e 4755 b88a 6ca3335a4412

      Pour more concrete. Once the mortar set I mixed and poured another 5”s of concrete. I could have poured it all at once but mixing concrete by hand is exhausting and by doing it this way I can remove any extra braces that could be in the way of screeding before doing a final pour. I also added in additional rebar since my 12” bars where already covered and wanted to make sure that the layers of concrete where bonded together.

    12. Step: 12

      Large 0b2a7c75 c98d 4637 b0e9 d0dbdc1f88a6

      Pour the final layer. After letting the previous layer of concrete cure about 20 hours I poured the final layer of concrete. I used a hoe to push the concrete down into all the corners and a wood dowel to vibrate the concrete by hand.

    13. Step: 13

      Large 16f3cf36 c1ad 4398 bb54 c304d119f4d2

      Screed the top. I used a flat piece of wood to screed the top of the concrete. Work the screed back and forth to level the concrete.

    14. Step: 14

      Large bfb23c3e 37c2 46c9 9bf1 34b5e2b74e8e

      Use a float. I let the concrete set about 30 minutes and then used a metal float to work the cream to the surface. I spent about 10-15 minutes working the surface.

    15. Step: 15

      Large 5f3f422e a157 4eae ab05 05116d421e47

      Steel Trowel. After using the float I waited about 1 hour and then used a steel trowel to finish the concrete. I did my best to get the surface as smooth and flat as possible. It isn’t perfect but it looks great!

    16. Step: 16

      Large 14707175 cda9 41ed a195 2fececbd5b8b

      Cover and keep moist. I covered the concrete with some boards and a sheet and made sure that nothing touched the wet concrete. I used a garden hose to keep the concrete moist over a 48 hour period.

    17. Step: 17

      Large 0766756e 18be 4d92 962c cbb62b9feef0

      Remove the formwork. Removing the outer frame was easy. The inner one required some cuts with a circular saw. I should have made some diagonal cuts in the interior panels before hand but not a big deal either way. After about 20 minsutes with a pry bar, hammer and circular saw I got the wood out. Sprayed off the concrete with a hose to clean it.

    18. Step: 18

      Large 8c1d6c4e 1d72 4f67 afd2 2fa894749ecf

      Pour in some lava rock. I poured 2 buckets of lava rockets in the inside of the pit. This creates a nice well drained surface for starting fires and covers the 3.5” foundation layer of concrete.

    19. Step: 19

      Large 46c435f0 4eb2 409e 8421 64c63366e2bd

      Before you light a fire. I recommend letting the concrete cure at least 30 days before lighting a fire. And I would recommend not letting a fire burn for longer than 2 hours for the first 3 months. It takes a long time for concrete to fully cure and you don’t want the moisture to expand inside it and cause cracking. Also be responsible and don’t make super large fires. The concrete is protected by the fire brick and lava rock but if you make giant bon fires and let them burn for hours and hours the concrete could crack. **Exclusive Feature**: Click here to download Homemade Modern's blueprints for this How-To!

    20. Step: 20

      Large d7a18430 e7f3 4705 9005 2a56179b0ed5

      **Exclusive Feature**: Click here to download Homemade Modern's blueprints for this How-To! Cut the Wood. The outer frame will be made of 4 panels that are 43.5” long. Each panel is made from 2 pieces of 2x4 and 2 pieces of 2x6. I used a circular saw to cut them but a compound miter saw would make this task a little easier. If you do use a circular saw I recommend using a speed square to make sure your cuts are nice and straight. I used L-brackets to join the panels at the corners. I recommend 6” L-brackets

Comments (3)



  • I am currently in the middle of this project. Waiting for the first layer of concrete to dry before I put in the fire brick. This project is very labor intensive. I had NO IDEA what I was in for... oh well no turning back now, and I'm sure it will look great. Thanks Ben!
    By JRT500, on August 4, 2015

  • Hi. I am planning on doing this project. Any idea on how many bags of cement are needed?
    By jaialaipro, on September 29, 2015

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Concrete Fire Pit

by Homemade Modern
Oct 21, 2014
Medium 992e0156 2f4a 45b4 bdd5 56395a2b0e46

This modern outdoor concrete fire pit can be built over a single weekend and is a great centerpiece for outdoor entertaining. This is not a difficult project but is time consuming and labor intensive. Concrete fireplaces and fire pits should be constructed carefully. When exposed directly to high amounts of heat the moisture trapped inside concrete can expand, causing the concrete to crack and in extreme situations explode. I lined the inside of the fire pit with fire brick and filled the bottom with lava rock to ensure that the majority of the heat from the fireplace is not coming in direct contact with the concrete. I built this fire pit in southern California so I didn’t have to worry about putting in footings that go below the frost line. If you are building this pit in a cold climate, I would recommend putting a sonotube footing under each of the four corners.

Project Steps

  1. Step: 1
    Huge 183a1a23 a395 426d be52 6b59ae5d0558

    Assemble the panels. I used 2.5” deck screws and 15” long pieces of 2x4 to make the 4 large panels for the outer frame

  2. Step: 2
    Huge f3b0748f 1af8 4d93 a954 c69a0cd591df

    Make the inner frame. The inner frame is made from 2 panels that are 23” long and 2 panels that are 20” long. Make sure to put the L-brackets on the inside corners of the frame since the outside ones will be buried in concrete.

  3. Step: 3
    Huge a9d5dd3c 3492 4f18 95d2 064f85adb7b4

    Place the frame and mark the hole. Place the frame in the desired location and mark about 6inches around the outside perimeter.

  4. Step: 4
    Huge 3e7ffd50 154d 4b26 aa4c 415f82d3d005

    Start digging. Since I am built this fireplace in southern California I didn’t have to worry about putting in footing below the frost line. If you are building in a cold climate I recommend putting in footings that go beneath the frost line under each corner. I dug about 8 inches down. I used a stamper to flatten and compact the soil at the bottom of the hole.

  5. Step: 5
    Huge 2060ca04 615a 4adf 9769 f00526e0de0e

    Spread some gravel. I spread about 3.5” of Quikrete ¾” gravel in the bottom of the hole and raked it as level as possible before stamping it down.

  6. Step: 6
    Huge 1efbee22 ce7d 4eab 8c68 6bf3a673cf4e

    Place the formwork. I placed the frames into position and measured the distance between the inner frame and outer frame to make sure the inner frame is properly centered.

  7. Step: 7
    Huge 47b59cce f7ef 4e18 b5cf 002bbad59b4e

    Secure and level the formwork. Once the frames are in the right position I used some scrap 2x3s to and deck screws to lock them into place. I then used a 6 foot level to make sure that the formwork was level. I used a rubber mallet to knock down the high corners to make it more level.

  8. Step: 8
    Huge e2102f43 97b5 44ac ac96 ee8a08ea5106

    Place the Rebar. I drove the rebar through the gravel and into the ground. I should have used longer rebar instead of the short 12” long vertical pieces. I then wired 3’ long pieces horizontally about 2” from the bottom of the hole.

  9. Step: 9
    Huge 4ff534b8 2fc2 438f 8bf0 90b185661fa3

    Pour the first layer of concrete. I started with a 3.5” deep pour of concrete that would serve as the foundation of the fire pit. I mixed the Quikrete 5000 in a wheelbarrow and shoveled it into place. Renting a mixer would have made this a lot easier but I enjoyed the exercise. Let the concrete cure at least 20 hours before laying the brick.

  10. Step: 10
    Huge 5c12a21d b606 453a a80f 0b335cd76bfc

    Lay the brick. Once the concrete has cured at least 20 hours get ready to lay the fire brick. I mixed the mortar per the instruction on the bag of mortar clay. I started with a thick base of mortar about ½” around the inner perimeter of the formwork I then placed the bricks one at a time. I spread mortar on the side of the bricks before place them so that they would stick together.

  11. Step: 11
    Huge 2a977325 252e 4755 b88a 6ca3335a4412

    Pour more concrete. Once the mortar set I mixed and poured another 5”s of concrete. I could have poured it all at once but mixing concrete by hand is exhausting and by doing it this way I can remove any extra braces that could be in the way of screeding before doing a final pour. I also added in additional rebar since my 12” bars where already covered and wanted to make sure that the layers of concrete where bonded together.

  12. Step: 12
    Huge 0b2a7c75 c98d 4637 b0e9 d0dbdc1f88a6

    Pour the final layer. After letting the previous layer of concrete cure about 20 hours I poured the final layer of concrete. I used a hoe to push the concrete down into all the corners and a wood dowel to vibrate the concrete by hand.

  13. Step: 13
    Huge 16f3cf36 c1ad 4398 bb54 c304d119f4d2

    Screed the top. I used a flat piece of wood to screed the top of the concrete. Work the screed back and forth to level the concrete.

  14. Step: 14
    Huge bfb23c3e 37c2 46c9 9bf1 34b5e2b74e8e

    Use a float. I let the concrete set about 30 minutes and then used a metal float to work the cream to the surface. I spent about 10-15 minutes working the surface.

  15. Step: 15
    Huge 5f3f422e a157 4eae ab05 05116d421e47

    Steel Trowel. After using the float I waited about 1 hour and then used a steel trowel to finish the concrete. I did my best to get the surface as smooth and flat as possible. It isn’t perfect but it looks great!

  16. Step: 16
    Huge 14707175 cda9 41ed a195 2fececbd5b8b

    Cover and keep moist. I covered the concrete with some boards and a sheet and made sure that nothing touched the wet concrete. I used a garden hose to keep the concrete moist over a 48 hour period.

  17. Step: 17
    Huge 0766756e 18be 4d92 962c cbb62b9feef0

    Remove the formwork. Removing the outer frame was easy. The inner one required some cuts with a circular saw. I should have made some diagonal cuts in the interior panels before hand but not a big deal either way. After about 20 minsutes with a pry bar, hammer and circular saw I got the wood out. Sprayed off the concrete with a hose to clean it.

  18. Step: 18
    Huge 8c1d6c4e 1d72 4f67 afd2 2fa894749ecf

    Pour in some lava rock. I poured 2 buckets of lava rockets in the inside of the pit. This creates a nice well drained surface for starting fires and covers the 3.5” foundation layer of concrete.

  19. Step: 19
    Huge 46c435f0 4eb2 409e 8421 64c63366e2bd

    Before you light a fire. I recommend letting the concrete cure at least 30 days before lighting a fire. And I would recommend not letting a fire burn for longer than 2 hours for the first 3 months. It takes a long time for concrete to fully cure and you don’t want the moisture to expand inside it and cause cracking. Also be responsible and don’t make super large fires. The concrete is protected by the fire brick and lava rock but if you make giant bon fires and let them burn for hours and hours the concrete could crack. **Exclusive Feature**: Click here to download Homemade Modern's blueprints for this How-To!

  20. Step: 20
    Huge d7a18430 e7f3 4705 9005 2a56179b0ed5

    **Exclusive Feature**: Click here to download Homemade Modern's blueprints for this How-To! Cut the Wood. The outer frame will be made of 4 panels that are 43.5” long. Each panel is made from 2 pieces of 2x4 and 2 pieces of 2x6. I used a circular saw to cut them but a compound miter saw would make this task a little easier. If you do use a circular saw I recommend using a speed square to make sure your cuts are nice and straight. I used L-brackets to join the panels at the corners. I recommend 6” L-brackets