How to Build a DIY Outdoor Fireplace for Backyard Hangouts

Gather ‘round and learn how to build your own outdoor fireplace

Alison Kasch
Written by Alison Kasch
Updated July 8, 2022
An outdoor fireplace
Photo: andrew / Adobe Stock
Difficulty

Challenging

Only DIY if you know what you're doing.

Time to complete

12 hours

Cost

$1,500–$6,000

Only buy supplies if you’re comfortable with advanced-level DIY.

Need professional help with your project?
Get quotes from top-rated pros.

What you'll need:

TOOLS

  • Tape measure
  • Level
  • Work gloves
  • Concrete mixing tub
  • Masonry hammer
  • Tamper (only needed when building a concrete slab foundation)

SUPPLIES

  • Mortar
  • Cinder blocks
  • Fire bricks
  • Hearth blocks
  • Ready-mix concrete
  • Gravel (Only needed when building a concrete slab foundation)
  • Two 1 1/2-inch-thick steel angles
  • Chimney cap
  • Cement board
  • Brick or stone veneers
  • Masonry nails

A backyard fireplace is the perfect warm and toasty gathering spot, a means for roasting marshmallows, and a way to get more use from your outdoor space when the nights get nippy. If the cost of a pro installing your outdoor fireplace or a premade kit burns you up, you can save big by going the DIY route. 

But know this: You should have some masonry knowledge if you want to tackle this project, as the planning and execution can be challenging without it. We get into s’more detail below.

Prepping to Build an Outdoor Firepit

Before you begin the build, check in with your local permit office to see if there are any codes or restrictions to abide by. Certain municipalities also require building permits for outdoor fireplaces. Either way, you don’t want to find out you needed this important documentation after you’ve already completed the project.

Design Your Fireplace

Prior to hitting the bricks, you’ll need a solid plan to help you figure out what materials you’ll need (and how many). Measure out the area you’d like to fill and create a rough sketch with the dimensions. 

  1. Pour a Concrete Slab, If Needed

    If you don’t already have a concrete slab to build on, prepare one by digging a ditch and tampering the soil down. Then, add a layer of gravel, pour the concrete, and allow it to cure.

  2. Lay Concrete Cinder Blocks

    Referring to your drawing and dimensions, begin laying the cinder blocks that shape the woodbox of your fireplace. Keep the center hollow for the firebox and create a “U” shape. Mortar the first layer of blocks to the concrete, then stack and mortar more blocks until you reach your desired height.

  3. Add a Lintel

    A lintel acts as a support beam that runs the length of your fireplace. Cut your steel angle to the right size (or purchase the exact length if it’s available). Lay the lintel across the front of the woodbox for support.

  4. Lay Hearth Blocks

    Lay as many hearth blocks as needed to cover the top of the wood box. Be sure to mortar securely around the seams.

  5. Build Your Fire Box

    Stack fire bricks on top of the hearth blocks to create your firebox. Mortar these together as you did for the wood box. 

  6. Add a Second Lintel to the Fire Box

    Cut the second steel angle so it runs the length of your fire box. Place this across the front of your fire box for added support.

  7. Install the Chimney Cap

    Once you’ve built the firebox, add the chimney cap to the top of the fireplace.

  8. Line the Exterior With Cement Board

    Cut your cement board to fit around the exterior of your fireplace. Securely mortar down each piece of cement board.

  9. Nail Down the Cement Board

    After you’ve laid down and mortared your cement board, nail it into place with masonry nails and a masonry hammer.

  10. Lay the Veneers

    Your last step is laying down your veneers of choice. Add a layer of mortar to the cement board and set your veneers firmly in place.

  11. Inspect for Cracks

    Before you set your fireplace on its maiden voyage, allow all your materials to dry fully. Then, examine the firebox and seal any cracks if needed.

Consider Building a Firepit

If reading through those steps left you feeling overwhelmed, you’re not alone. This project is best suited for those with prior masonry knowledge. From the design to building the actual structure, it’s not something the average DIY-er can typically pull off. 

You could also go another route; a firepit costs less than an outdoor fireplace, plus it is much more DIY-friendly (and will toast marshmallows all the same). These can be gas or wood, though gas varieties require the knowledge of a professional. Either way, there are tons of unique fire pit ideas, so you can still create a gorgeous design that will light up your outdoor space.

Think About Professional Installation

Professionally installing an outdoor fireplace costs quite a bit more than the DIY, but it’s worth the investment if you’re dead-set on an outdoor fireplace. This is a build you shouldn’t attempt unless you’re totally confident that you can safely accomplish it. When in doubt, reach out to a local mason.

Need professional help with your project?
Get quotes from top-rated pros.