How to build a fire pit with cinder blocks (1)

How to build a fire pit with cinder blocks

A fire pit is a great way to enjoy outdoor living, especially on cool evenings. Not only does it provide warmth and comfort, but it can also be a focal point for gatherings with family and friends. If you’re thinking of adding a wood-burning fire pit to your backyard, here’s a simple guide on how to build a fire pit with cinder blocks.

Can you build a fire pit with cinder blocks? Is it safe?

A fire pit with cinder blocks is an effective, straightforward method of building propane or wood-fired outdoor fire for all sorts of purposes. You can build one in your own backyard even if you’re not quite the handyman around the house. At best, it should take no more than two hours to complete, depending on the size you want.

Building a cinder block fire pit is safe, but there are some things you need to know before you start. Be sure to keep the fire pit away from any trees, bushes, or other flammable objects. It’s also important to make sure the surrounding area is clear of any brush and/or leaves so they don’t catch on fire.

How to build a fire pit with cinder blocks

Tools Needed

  • Cinder blocks (8 per fire pit)
  • Level
  • Shovel
  • Circular saw (not necessary but recommended)
  • Stone or brick chisel (not necessary but recommended)
  • Concrete mixer (optional, may use five gallon bucket instead)
  • Spray bottle with water
  • Hammer
  • Chisel

Step 1: Arrange Cinder Blocks

Start by laying out the cinder blocks on a leveled surface. Arrange them in a circular design, leaving room for your fire pit. You may find that you need to adjust the size of your fire pit as you begin to lay out the blocks. By doing so, your finished product will be a perfect fit.

Step 2: Level the Cinder Blocks

Once you have the cinder blocks in place, use a level to make sure they are all even. Adjust as needed until each block is sitting straight and true. This is important, as it will ensure your fire pit is stable and safe.

Step 3: Dig Out the Center of the Cinder Blocks

Next, use a shovel to dig out the center of each cinder block. This will create a space for your fire pit and also allow air to circulate beneath the blocks. Be sure to keep the sides of the hole clean, as any dirt or debris could cause the fire pit to collapse.

Step 4: Lay Brick or Stone in the Center of each Cinder Block

Once you have dug out the center of each cinder block, lay brick or stone in the hole. This will create a more finished look and also help to stabilize the blocks. You can either use the same type of brick or stone as your fire pit or go with a contrasting color for a different look.

Not only that – you can also use your cinder blocks to build a patio or even an outdoor fireplace (like the one pictured above).

Step 5: Pour Concrete around the Cinder Blocks

Now, pour concrete around each cinder block. This will help strengthen the structure and prevent shifting, as well as seal in the brick or stone. Make sure to fill all the spaces between the blocks and use a trowel to smooth out the surface.

Step 6: Let the Concrete Set

Allow the concrete to be set for at least 24 hours before using your fire pit. You may want to wait even longer, especially if you are using cinder blocks with a hollow cavity. The longer you wait, the stronger your fire pit will be.

Step 7: Grate Lava Rock

Next, grate lava rock in preparation for adding it to the concrete. Use about one pound of lava rock per square foot of concrete. You can find lava rock at most home improvement stores.

Step 8: Add Lava Rock to the Concrete

Now, add the lava rock to the concrete. Use a shovel to spread it around and make sure it is evenly distributed. You may want to use a trowel to smooth out the surface.

Step 9: Allow the Concrete to Cure

Finally, allow the concrete to cure for at least seven days before using your fire pit. This will ensure that it is fully cured and stable.

Once your concrete has cured, you are ready to use your cinder blocks fire pit.


Q: How deep should I make my fire pit?

A: This can vary depending on your preferences. However, it is usually recommended to leave the center hollow so the fire has room for air. The majority of people choose to have a depth of about 12 inches.

Q: What do I fill my cinder blocks with?

A: Most people choose to fill their cinder blocks with sand. However, you can also use cement or bricks and stones if you want a more finished appearance.

Q: Is there anything I should do before I use my fire pit?

A: Yes, it is recommended that you waterproof your cinder block fire pit by applying an elastomeric coating. This will help to protect the concrete from heat damage and will also make it easier to clean.

Q: Can I use my cinder block fire pit all year long?

A: Yes, you can use your cinder block fire pit all year long. However, you should take caution when using it in the winter months. The fire can cause the concrete to become extremely hot and may even crack under extreme temperature changes.

Q: What kind of wood should I use for my fire pit?

A: You can use any type of wood for your cinder block fire pit, although some people prefer to use more dense types of wood like oak or hickory. Softwoods like pine will create more smoke and sparks.

Conclusion: How to build a fire pit with cinder blocks

Building a fire pit with cinder blocks is a simple and affordable way to create a backyard gathering spot. By following these simple steps, you can have your own fire pit up and running in no time. So gather your family and friends around the warmth of a crackling fire this fall – the perfect way to spend an evening outdoors.

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