Great for year-round entertaining, fire pits are a welcome addition to any backyard. Building one is a satisfying weekend project, great for advanced DIYers. All you need are some basic tools, supplies, and a few friends ready to help speed you along.
- Tape Measure
- Shovel (Square & Pointed)
- Pick Axe
- Circular Saw
- Flat Spade
- Flat Trowel
- Mortar Tub
- Masonry Brush
- Rock Hammer
- Diamond Blade
- Grout Bag
- Brick Jointer
- Hand Broom
- Wooden Stakes
- Spray Paint
- Concrete Blocks
- S-Type Mortar
- Small Pipe
- 800 lbs. of Concrete – Quick-setting
- Duct Tape
When taking on this DIY task, be sure to equip yourself with the proper safety gear. Throughout the video, we’ll alert you regarding when you should and should not use the safety gear.
Define fit pit area. Start by determining where you’d like your fire pit. If you’re building near a retaining wall, as we are in this project, a good rule of thumb is to build it at least three feet from the wall. Make your measurement and mark the area with spray paint. Wherever you decide to build your fire pit, you’ll need a solid foundation. If you’re building on grass, you’ll need to pour a concrete foundation. We’ll walk you through how to do that in the next four steps. If you’re building on pavers or existing concrete, skip to step six.
Once you’ve defined your pit area, mark the four corners with spray paint, 51 inches from corner to corner. Then spray paint the outline from corner to corner. You’ll now create a level surface for your foundation. Start by removing grass with a pick axe and shovel. Then check for level on each side and dig or fill in areas as needed. Use a square shovel to scoop up any excess dirt and flatten the area. Check for level again.
Build concrete frame. Once you’ve confirmed the area is level, you’ll start building a concrete frame for your foundation. Mark cuts on your 2×4’s with a quick square. Then cut them in two 54 inch and two 48 inch pieces. Have a friend help you screw the 2×4’s together, so the ends of the longer pieces are flush with the back of the shorter pieces. Connect each corner with two screws.
Position the concrete frame. Position the concrete frame into place and level each side of the box by adding or removing soil underneath the box. It can be helpful the mark the area with spray paint again and remove the frame. Once the area’s ready, put the frame back into place and check for level. Confirm the frame for square by measuring corner to corner on each side. If it’s perfectly square, the measurements should be the same.
Use a sledgehammer to drive wooden stakes at each corner of the frame. Once your stakes are in place, have a friend level the frame while you fasten the stakes to the frame with screws. Once the stakes are attached, confirm everything is still level. Then place soil along the edges to prevent concrete from spreading outside the framed area.
Pour concrete. For convenience, we recommend mixing your concrete in a wheelbarrow. Pour ready-to-use dry concrete mix into the wheelbarrow and add water according to manufacturer’s instructions. Use a hoe to mix the concrete in the wheelbarrow until it is smooth. Then use the wheelbarrow to pour the concrete into your frame. Mix and pour until you’ve filled the box with concrete. Smooth with a flat trowel. Then let dry according to instructions before continuing.
Remove concrete frame. Once the concrete is completely dry, remove the screws connecting the stakes to the frame as well as the screws holding it together. Do this at each corner. Then remove the 2×4’s from your new concrete block.
Outline block area. The walls of your fire pit will be made of concrete blocks. To ensure the blocks, each of which is eight inches wide, will be flush with the edges of your concrete pad, mark eight inches in at each corner. Then use a level or a straight edge to draw a straight line across the pad. Do this for each side.
Mix block mortar. Mix seven shovelfuls of sand for every half bag of S-type mortar you use. Mix the sand and mortar blend with a hoe until it is thoroughly mixed without any sand color visible. Add water in small increments, mixing until the mortar reaches a peanut butter consistency. When your mortar sticks to the trowel, you’re ready to go.
Lay first block. Apply a generous amount of mortar to the cement base with a trowel. Lay the mortar in the same pattern as the block, so it will adhere to the bottom edges of the block. Place the block on top of the mortar and check it for level, side to side and front to back, adjusting as needed. Use your trowel to move any excess mortar up the sides of the block.
Lay second block. Apply the mortar to the cement pad in the same pattern you used for the first block. Then apply some on the side edge of the new block. Set the block into place and check for level, side to side and front to back, adjusting as needed. Then smooth the mortar around the edges
Scratch coat. As you work, apply a scratch coat of mortar to the sides of the blocks. This will hide block seams and create a clean look on the inside of your fire pit and provide a surface for decorative rocks adhere to on the outside.
Create weep hole. A weep hole is an essential element of any fire pit, as it prevents it from collecting water. To build one, pick a small piece of rubber pipe, at least 12 inches long and about the width of a pencil, and place it along the first block you laid. Cover it with the mortar for the perpendicular block. Be sure to move the pipe around as you work so it doesn’t set in place. Once your mortar starts to set, pull the pipe out.
Stagger blocks. Once you reach the second level of concrete blocks, flip the pattern so the seams are staggered. The side that has three blocks on the first level should now have two blocks on the second level.
Mix rock mortar. Mix four shovelfuls of sand with half a bag of S-type mortar. Mix the sand and mortar together, adding watering until it reaches peanut butter consistency.
Lay rock. Determine the lowest point of your fire pit and begin laying mortar in that corner. Work in rows, beginning each row with a corner piece. Apply the mortar to the back of each stone. Then push it into place. Stagger the joints of your rock, even on the corner pieces. This will be the most time-consuming part of your project. Asking a friend to help will speed it along. Once all your rock has been installed, allow the mortar to dry completely before installing capstones. Remember to remove the pipe for your weep hole as the mortar dries.
Cutting rocks. You may need to cut some rocks for them to fit properly. We recommend doing this with either a rock hammer or a grinder with a diamond blade.
Lay out capstones. Have a friend help you set the capstones in place. Start with the corner stones, leaving about an inch of overhang.
Mix capstone mortar. The mortar you’ll use for the capstone is made with the same ratio as the mortar used to set the concrete blocks, seven shovelfuls of sand for every half bag of S-type mortar. Turn the sand and mortar until it is thoroughly mixed. Then add water in small increments, mixing until it reaches a peanut butter consistency. When the mortar sticks to your trowel, you’re ready to set your capstones.
Set in capstones. Start with the thickest capstones first. Have a friend pick up the capstones as you lay the mortar in place, adjusting the amount you use in order to keep the stones level. As you work, check for level, side to side and front to back. Once the capstones are set, allow the mortar to dry for at least an hour before continuing.
Tape. Use duct tape to define grout lines, wrapping the tape underneath the bottom edge of the capstones to the top edge. Do this on both the outside and inside of the fire pit.
Grout. You’ll make grout with the same ratio as the mortar you used for the concrete blocks and capstones, seven shovelfuls of sand to each half bag of S-type mortar. Use a grout bag to pipe the grout into the gaps. Allow the grout to begin setting per manufacturer’ instructions. Then use a brink jointer to smooth. Brush away any extra grout with a hand broom.
Fill pit. While you’re waiting for the grout to set, carefully fill the pit. Start by pouring all-purpose fire safe stone or gravel into the corner where the weep hole is located. This will help with drainage. Fill the pit halfway to three-quarters full of sand to raise the fire and provide a bed for ashes. Touch up the grout if needed.
Your project is complete! Step back, admire your hard work, and start planning your first backyard get together around your new fire pit.