11 Best Tips on How to Build An Outdoor Fireplace

Have you opted to elevate your backyard? Perhaps you are pondering how to construct a fireplace. Is it right for your family and lifestyle?

The amazing thing about the Fremont Outdoor Fireplace Kit is that it not only serves as an aesthetically pleasing element of patio design but also creates an ideal environment for relaxation.

Imagine gathering with friends and loved ones around the fire, where tales can be exchanged along with its comforting flames! So in this blog, we will give our best tips on how to build an outdoor fireplace!

Why is it worth it?

how to build an outdoor fireplace: a man relaxing in his newly built outdoor fireplace

Are you looking to take your outdoor living space from great to extraordinary? If so, constructing an outdoor fireplace would be a perfect way! Not only will it create a space that people love to congregate in but also transform your yard into a favorite spot for family and friends.

Outdoor fireplace ideas are best for events like barbeques, pools, hot tubs, pergolas, and decks. Outdoor kitchens are all key elements when it comes to bringing together gatherings – much like outdoor fireplaces.

Another bonus is that there are several reasons why having one of these in your backyard makes total sense:

  • A fireplace offers more of a living space ambiance outdoors.
  • A fireplace can double as a privacy wall in your yard.
  • If your outdoor space is at a premium, a fireplace can take up less space than a firepit setting.
  • A fireplace is less smokey than a firepit and its flames are better protected from breezes, gusts, or changes in a wind’s direction.

What you’ll need

Here’s what you’ll need to build an outdoor fireplace:


  • Protective gloves
  • Tamper
  • Tape measure
  • Masonry hammer
  • Hammer
  • Concrete trowel
  • Shovel
  • Bubble level
  • Circular saw
  • SquareHacksaw
  • Hoe
  • Mortar mixing pan
  • Wood or metal stakes


  • 33 full concrete cinder blocks, 8-inch by 8-inch by 16-inch
  • 12 half concrete cinder blocks, 8-inch by 8-inch by 8-inch
  • Manufactured veneer stone
  • 6 cement backer boards
  • 2 metal flue caps, 24-inch by 24-inch
  • Mortar
  • 26 80-lb. bags of quick-set concrete
  • 6 50-lb. bags gravel
  • Nails, 2 1/2-inch
  • 2 two-by-sixes
  • Rebar, 42 inches by 6 feet
  • 2 steel angles, 1 1/2-inch by 72-inch
  • 6 hearth blocks, each 42-inch by 32-inch
  • Masonry nails

Steps on How to Build An Outdoor Fireplace

1) Decide where you’ll build your fireplace

For maximum safety and pleasantness, outdoor fireplaces should be situated close enough to the home for convenience but a sensible distance away.

Local regulations typically require that an outdoor fireplace remain at least 20 feet from the house to prevent any risk of accidents or inconveniences.

Additionally, patio covers should not obstruct airflow as this can cause smoke buildup; furthermore, water must flow downwards and away from the area surrounding your fireplace as collected moisture may lead to concrete pad cracking over time.

You have to decide at this point whether you want a brick fireplace, or you want one of those wood-burning fireplaces.

2) Level the Area For the Fire Pit

Dig a 70 by 56-inch section of ground, then flatten and level the area with a tamper. Once that is complete, spread 2 inches of gravel to smooth it out for an even surface.

Finally, use the tamper again to make sure everything is firmly packed in place.

3) Build the Concrete Pad Form For The Fireplace

Using the hammer and nails, construct a concrete form out of two-by-sixes that are cut into sections measuring 68 inches long and 40 inches long.

Place it atop the gravel base and employ a square tool to ensure its rectangular shape is perfect.

Afterward, trim down rebar pieces so they fit correctly inside the form’s perimeter before adding wood or metal stakes around it for stability when pouring in concrete later on.

4) Pour the Fireplace Pad Concrete

Start by stirring together the quick-set concrete and hoe in a mixing pan. Then, slowly pour half of it into your form before laying out the rebar around its perimeter at six inches from each edge.

5) Allow the Concrete to Cure

After one to two days, the forms can be removed and the concrete should be ready for use in four to five days, these will allow the concrete footing to be sturdy as you need it to be for your fireplace. However, it is best to wait a full month until its optimal curing time has been reached.

6) Lay the Fireplace’s Wood Box

For a strong and sturdy foundation, arrange seven full-size blocks in the shape of a U: three at the back and two on each side. Place two half-sized blocks at both ends of this structure as well.

Then, use some mortar to firmly attach these blocks onto your concrete pad; this forms your first level box out of three total courses.

For the second course, switch up block placements – make sure that seams from below match perfectly with those in between the upper layers’ center points. Lastly, duplicate your initial bottom layer for a balanced finish!

7) Create the Lintel

Take the hacksaw and cut your steel angle to a length of 68 inches. You can then place it across the front of your wood box as a lintel for extra support.

8) Lay the Hearth Blocks

Firmly secure the two hearth blocks on top of the wood box with mortar. Create a seamless bond between each block by applying an even layer of mortar to their edges.

9) Build the Firebox

Construct the firebox atop the hearth blocks, which have a smaller dimension compared to that of the wood box.

For each side and back use two full-sized blocks, while for either side use one half-sized block. Assemble three courses in line with how you did earlier on about forming the wood box. If you have an outdoor gas fireplace, however, you may have to try building it differently.

Utilizing a hacksaw trim down your steel angle to 48 inches before positioning it at the front as a lintel support system for increased stability.

10) Add the Chimney Caps

Add the two chimney caps side-by-side on top of the firebox.

11) Lay the Veneer Stone

Cut and set the cement board across all sections of your fireplace that will be clad with veneer stone.

Secure it in place by applying mortar, followed by fastening masonry nails. Lastly, evenly apply Mortar to adhere the stones onto their new home – the cement board!


Before building your outdoor fireplace, you have to check local building codes before you start to save yourself the hassle and just enjoy your newly built fireplace. Local codes are important to ensure safety especially if you have a neighbor.

If you don’t want to build a fireplace, you can try to build a portable fireplace. Unlike most outdoor fireplaces, you can move these from place to place depending on where you’ll need them.

Don’t be too complacent about building your place as it’ll need to be durable and long-lasting. Make sure your fireplace opening, wood storage, and fire brick can withstand extreme heat when you start to burn wood. There are fireplace kits in the market to make sure you’re building it right.

Start having your fireplace DIY Project today!

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