Step-by-Step Guide: How to Build an Outdoor Fireplace

An outdoor fireplace is an excellent addition to any home’s exterior. They make your outdoor space more comfortable and war,m and they can boost the value of your home as an added bonus. 

How to Build an Outdoor Fireplace

Before you pay someone else to build an outdoor fireplace for you, however, you should consider making it yourself! Not only will this be a rewarding project for you to work on, but it’s not as complicated as you might think. 

Read on to find out how to build an outdoor fireplace from scratch.

We’ll be including factors you need to consider beforehand, a list of the tools and materials you’ll need, and step-by-step instructions for when it’s time to get building! Don’t forget to check out our FAQ section below for extra information. 

Before You Start Building 

We know you’re eager to start building your outdoor fireplace, but before you do, there are a few things you need to think about: 

Spatial Requirements 

An outdoor fireplace might not take up as much space as some other outdoor furnishings, but you still need to make sure you have enough space to build and use your fireplace safely. 

You’ll need to ensure that your fireplace is at least 20 feet away from your home or any other furnishings like patio covers.

If you don’t have at least this much outdoor space, including the space you’ll need for the fireplace (70 x 56 inches), building an outdoor fireplace is not a good idea, and you likely won’t be able to do so legally. 

Laws And Permits 

When we consider legal issues, different areas have different laws when it comes to building on your property, especially for things like fireplaces which have an impact on the air quality. 

Before you start gathering materials and planning your building work, it’s worth contacting the permitting office in your area.

They will be able to tell you whether you need to apply for a building permit and whether there are any measures in place to maintain the air quality in your area (in which case, wood-burning fireplaces might be prohibited). 

Tools And Materials

Before you get started, make sure you have all the materials and tools you need. These will be as follows: 

Building Materials 

  • Veneer stone 
  • Mortar 
  • 12 x half concrete cinder blocks (8 x 8 x 8 inch)
  • 33 x full concrete cinder blocks (8 x 8 x 16 inch) 
  • 6 x hearth blocks (32 x 42 inch)
  • 6 x 50 lbs gravel 
  • 26 x 80 lbs concrete (quick-set)
  • 6 x cement backer boards 
  • 2 x flue caps (metal, 24 x 24)
  • Rebar (6 feet x 42 inch) 
  • 2 x steel angles (1.5 inch x 72 inch)
  • Masonry nails 
  • 2.5-inch standard nails 
  • 2 x two-by-six 


  • Hoe 
  • Shovel 
  • Hacksaw 
  • Standard hammer 
  • Masonry hammer 
  • Stakes (metal or wood)
  • Square 
  • Circular saw 
  • Mixing pan for the mortar 
  • Tape measure
  • Building gloves 
  • Trowel for the concrete 
  • Bubble level 

Building An Outdoor Fireplace: Step By Step

Building An Outdoor Fireplace Step By Step

1. Choose A Location 

The first thing you need to do when it’s time to start building your outdoor fireplace is choosing a suitable location. 

Depending on the size of your backyard, you may or may not have a lot of options to choose from. As we mentioned earlier, your fireplace needs to be a minimum of 20 feet away from any buildings or furnishings.

That includes patio covers, which can keep smoke trapped underneath. With that being said, you also don’t want to position your fireplace so far away from your home that it’s difficult to get to. 

Make sure that you put the fireplace somewhere that allows water to drain away. If water is allowed to pool around the concrete pad or seep under the fireplace, you’ll end up with structural damage that could take a lot of time and money to repair. 

2. Clearing And Excavating 

To prepare the ground in your chosen location to receive the fireplace pad, you’ll need to clear and level it. 

Remove any objects and debris before excavating a 70 x 56-inch patch of land. Make sure it’s flat and level before using your tamper to tamp down the soil. 

Once this is done, get one of your bags of gravel and spread a 2-inch layer over the cleared and excavated area. Make sure it’s flat and even before you proceed to the next step.

3. Make The Pad Perimeter 

Your fireplace pad will be made of concrete, but before you can start working with the concrete to make the pad itself, you need to lay the perimeter, also known as the pad form. 

For this part, you’ll need your two-by-sizes. Cut both of them so that you end up with two pieces that measure 40 inches in length and another two that measure 68 inches. 

Next, take your hammer and your standard nails to put the form together and position it on the gravel.

This will need to be perfectly squared off, so take your square and measure it before cutting your rebar so that it’s the correct size. 

Get your stakes and position them around the form, and you will have a finished pad form for your fireplace.

4. Add Concrete 

You can now go ahead and add the concrete to make the pad itself. To do this, you’ll need your mixing pan and your hoe. 

Using the hoe, mix the concrete directly in the mixing pan. Once you have enough concrete, carefully pour half of it into your pad form.

Do NOT pour all of the concrete in at this stage because you’ll need to place the rebar first. It should be roughly 6 inches away from the edges of your form. Once you’ve placed the rebar, you can add the rest of your concrete. 

5. Mortar The Wood Box 

Before you complete this next step, wait at least one day, possibly two. This gives the concrete time to cure before you remove the forms. 

Having removed the forms, you can start laying your full-size blocks by mortaring them onto the pad in a ‘U’ formation.

This involves putting three blocks at the back with two blocks on each side. Use your half-size blocks to make the ends of the shape. 

For the next course of blocks, you will need to alternate so that the seams in the bottom layer are in the middle of each block in this layer. When you get to the third and final layer, make sure the blocks are mirroring the positions of the bottom layer. 

6. Prepare And Place Lintel 

You’ll need a lintel for support during the next steps of building your fireplace, and you’ll be making one out of a steel angle.

Take your hacksaw and cut one of your two steel angles so that it’s 68 inches long. 

Once your lintel is the correct length, lay it across the wood box at the front. This should provide enough support for the hearth blocks. 

7. Mortar Hearth Blocks 

Now using mortar, secure your two hearth blocks to the wood box. Make sure you also put mortar into the seam where the hearth blocks meet on top of the box. 

8. Make a Firebox 

You’ve already made the wood box for your outdoor fireplace, so making the firebox shouldn’t be too complicated.

That’s because it’s basically just a smaller-scale wood box that goes on top of the hearth blocks you just mortared in place. 

You’ll need four more full-size blocks for this as well as two half-size blocks. Instead of laying three full-size blocks along the back of the fireplace, you’ll just use two.

You’ll then have two full-size blocks left to put one on either side. Just like you did for the wood box, you’ll finish the ‘U’ shape with a half block on each side at the ends. 

Repeat this for three courses or layers, remembering to alternate the seam placement exactly the same as with the wood box. 

9. Make A Second Lintel

You should have another unused steel angle left at this point, and you’ll use it to make a second lintel. This time, you’ll need to cut it shorter to 48 inches. 

Lay the lintel on top of your firebox along the front to provide support for when you add the chimney caps. 

10. Place Flue Caps

Take your two metal flue caps and put them on top of the firebox. They should be aligned next to one another. 

11. Prepare And Place Cement Board 

At this point, you are almost done building your outdoor fireplace and just need to add the finishing touches.

If you prefer, you can skip this step and go straight to step 12, but we recommend completing this step first to make your fireplace more durable. 

Cut your cement board to the right size (enough to put across any areas you’ll be finishing with veneer stone), and use mortar to secure the cement board.

Bear in mind that mortar won’t be enough to hold the cement board in place long-term, so use your masonry nails to make sure everything is secure. 

12. Finish With Veneer Stone 

For the final step of the project, add mortar to the cement board and lay the veneer stone. If you choose not to add the cement board, you can just mortar the stone directly onto the blocks instead. 

Why Build An Outdoor Fireplace? 

Circular outdoor brick fire pit. bench and cushions.

If you’re still going back and forth on the idea of building an outdoor fireplace, there are many reasons why we think you should go ahead and do it. 

For one thing, you’ll enjoy spending time in your backyard much more if there’s an outdoor fireplace, especially as the weather begins to cool down.

Not only will your yard feel warmer with an outdoor fireplace, but it will have more of an ambiance. 

Outdoor fireplaces typically take up less space than firepits and produce less smoke, so if you’re weighing up the benefits of building a fireplace instead of a fire pit, these two factors are important to consider. 

Plus, you can even position your fireplace in such a way that it doubles as a wall, making your outdoor space more closed-off and private. 

Frequently Asked Questions 

How Long Does It Take To Build An Outdoor Fireplace?

How long it takes you to build your outdoor fireplace will depend on a few external factors.

For example, if you have a lot of other commitments in your life or you have bad weather in your area, it will likely take you longer.

However, on average, you can expect to spend anywhere between 7 and 10 days building an outdoor fireplace. 

How Much Should I Spend Building An Outdoor Fireplace?

The overall cost of building an outdoor fireplace will vary depending on which specific materials you choose and which manufacturer you choose to buy from.

Bearing that in mind, building an outdoor fireplace can cost as little as $200 to $400.

If you buy more expensive materials or want to make a larger fireplace, you could find yourself spending anywhere between $1,500 and $20,000.

You can easily adjust your fireplace building project to your budget.

Will Building An Outdoor Fireplace Increase My Home’s Value?

Yes, adding an outdoor fireplace to your yard can significantly add to its resale value. In fact, if you do a good enough job building your fireplace and keep it in great condition through regular maintenance, you could increase your home’s value by up to 20%.

Final Thoughts 

Building an outdoor fireplace is a project that might require planning permission, and you should also have a good level of building experience under your belt before you attempt it yourself. 

As long as building a fireplace outdoors is allowed in your area and you have a decent level of skill when it comes to building, creating your own outdoor fireplace shouldn’t be a difficult task. 

Make sure you leave enough time for the cement pad to cure and that water is not able to collect under the pad, and you should have a structurally-sound fireplace that you can use for many years to come.

Stevie Morris