Blocks are one of the best materials to use for building your fire pit since it’s relatively cheap and easy to build with. Additionally, it looks fantastic in your backyard, no matter what block material you choose. But that leads to a burning question: What are the best blocks to use for a fire pit?
The best block material to use to build your fire pit is fire brick because fire brick is designed to withstand heat up to 1,800 degrees Fahrenheit without flaking, cracking, or exploding. For the best shape, trapezoidal, rectangular, and blocks with a 1″ lip are all excellent options.
We know that you want to build your fire pit right and make it 100% safe for your family and friends to enjoy with you, so we’ve written this post today to teach you which materials you can safely use to build your backyard fire pit.
First, we’ll go over the five fire-safe materials, and then we’ll jump sides and explain what blocks you should avoid using to build your fire pit. Finally, we’ll wrap this post up by giving you the details on the best shape of blocks to use, plus help you determine which fire pit shape is right for you.
What Are The Best Blocks To Use For A Fire Pit?
The best block material for a fire pit is fire brick because fire bricks are refractory materials. Refractory materials can withstand high temperatures (in addition to extreme pressure or chemical reactions) and therefore can be used safely in a fire pit.
As for shape, trapezoidal blocks, rectangular blocks, and blocks with a 1″ lip are all great options.
Fire brick is usually found in kilns as well as the lining of fireplaces and fireboxes. In contrast, cement is more commonly used to build other things, such as cement sidewalks, patios, pool decks, and driveways.
While we recommend fire brick as the best option for constructing your fire pit, they aren’t the only materials out there.
Keep reading to learn more about three other types of fire pit-safe blocks.
What Is The Best Material To Use To Build A Fire Pit?
Firebrick is our top recommended material to use to build your fire pit since the blocks are relatively cheap, easy to work with, and can be found at most home improvement stores.
Let’s take a look at five materials that are fire-pit approved.
Fire bricks, also known as ceramic refractory bricks or kiln bricks, are a safe type of brick you can use to construct your fire pit. Fire bricks are one of the best material options since fire brick is any brick that can withstand heating and cooling repeatedly at various temperatures – i.e., it won’t flake or crumble.
Fire bricks can also stand up against different atmospheres. So, fire brick is a great choice to build your fire pit with, no matter where you live!
Furthermore, fire bricks are not like your ordinary brick in that fire bricks can withstand incredibly high temperatures (up to 1,800 degrees Fahrenheit). Traditional brick and mortar cannot – at least not for as long – since the conventional kind is typically only made from dried clay (however, in some instances, brick can informally mean chemically-cured blocks).
Now, there are two kinds of fire brick: hard brick and soft brick.
- Hard brick: These bricks are dense, durable, and used to provide structural support. Hard bricks are often the go-to for constructing appliances that come in contact directly with flames, such as the main component of a firebox, chimney, or kiln. We recommend using hard fire brick to build your fire pit.
- Soft brick: Unlike hard bricks, the soft variety is lightweight and made from refractory clay containing combustible materials. When heated, the combustible material burns out, leaving pockets of air inside (picture a sponge), which helps insulate the brick. Soft bricks are an excellent choice for building electric kilns.
Perhaps one of the most popular, concrete is another good choice for building your fire pit since it’s also flame retardant, easy to work with, and incredibly sturdy. You can use poured concrete or piece together concrete blocks using construction adhesive.
We recommend the Loctite PL 500 Landscape Block Adhesive.
Though concrete is popular since it’s relatively inexpensive and a beginner-friendly fire pit, it may not be as aesthetically pleasing as other construction block options, such as stone. Some homeowners opt to use colored or tinted blocks of concrete that have a different color from the typical natural gray most concrete has.
For example, instead of traditional gray, you could use concrete blocks in colors of beige, white, cream, or brown.
Do be aware that we recommend against using compressed concrete since compressed concrete wears down after repeated use, which leads to potential explosions from your fire pit.
Paver blocks are another good option to use to build your fire pit. Pavers, also known as paving stones, are flat pieces of construction material made of brick, concrete, or stones. They’re commonly used for exterior floorings like decks, patios, walkways, and driveways.
Pavers are a great option because they are incredibly durable (up to four times more durable than concrete) and can last 30 – 50 years!
Because they are also heat-resistant, they are a safe option to use as a building material for your fire pit. For your fire pit, we recommend going with concrete pavers over brick or stone for your fireplace, though any non-flammable paver will do (for the record, concrete is the cheapest option, then brick, followed by natural stone).
Finally, one last thing to note about pavers: though pavers are a little more expensive than other fire pit construction options like concrete, pavers hold up better and add greater value in the long run. That’s something worth considering as a homeowner!
Flagstone is a hard stone, so it’s a great type of block for building your fire pit. Many love the elegant and beautiful look that flagstone creates when paired with fire – think of those long, flat stones that stack together with a semi “uneven” look.
The downside to choosing flagstone is that it’s one of the more expensive fire pit block options.
Granite is also a durable hard stone that can be used to construct your fire pit. It’s very dense, which means less of a chance for the material to absorb water, meaning that your fire pit is less likely to explode once heated. It’s also resistant to cracking, rusting, and staining – an essential factor to consider since your fire pit will remain outside.
Additionally, many homeowners choose granite because of its appealing aesthetic. Granite comes in various colors and even patterns, though the color proportion and patterning vary due to where the source of molten rock was cooled.
You can find white, black, red, blue, pink, and even green granite!
Which Blocks Should I Avoid Using In My Fire Pit?
Avoid using compressed concrete, sandstone, limestone, pea gravel, and river rock to build your fire pit. These materials have a chance of exploding since they degrade when exposed to high heat.
So how does this happen? When heated in a fire, water trapped inside these materials moves away from the heat source and becomes vaporized or tries to become vaporized. Any water and steam that gets “stuck” cannot vent out of the material. Therefore pressure builds, and an explosion can happen.
Of course, we recommend ensuring that you build your fire pit correctly and out of fire-safe materials to avoid dangerous explosions.
Using fire brick or a metal liner on the inside of your fire pit with an interlocking outside material such as pavers or flagstone is a tried-and-true fire pit design. Concrete paver kits are another safe option!
What Block Shape Is Best To Build A Fire Pit?
While you could make your fire pit in any shape that you want, square and circular-shaped fire pits are the easiest to construct.
Trapezoidal-shaped blocks work best for building circular-shaped fire pits since they have tapered edges, while rectangular blocks make for an excellent square-shaped pit as they interlock nicely together.
You may also want to consider adding blocks with a 1″ lip on the interior because they help to keep the surrounding blocks secure and aligned.
Trapezoidal blocks are best for when you want to build a circular-shaped fire pit. You’ll also need to get small spacer blocks to help you achieve the curve.
There are three common sizes in fire pit blocks:
- 8”x 3”x 4”
- 10.25”x 3.5”x 7
- 11”x 4”x 6”
Rectangular blocks are best to use when constructing your fire pit into a square shape.
If you’re building this shape of a fire pit, start at the corners with large blocks and complete the edges adding a spacer block as needed or to your design preference.
Blocks With a 1” Lip
Blocks with a 1″ lip on the inner side near the bottom help secure the stacked blocks and keep them aligned. While these blocks are acceptable for use in fire pit construction, be aware that as you add a new row upon the last, each row of blocks will stack slightly recessed from the edge.
What Shape Should A Fire Pit Be?
Whether you should design a square or circle fire pit is ultimately up to you – do you prefer modern design, structure, and formality, or are you the house host that loves to soak in all the chit-chat?
Square Fire Pit
Square-shaped fire pits create a formal, structured look thanks to the straight lines and 90-degree angles. They also play well off of today’s modern home look, which is strongly geometric.
Moreover, square fire pits are also suitable for smaller spaces since they pair well with a streamlined sofa, long line of seating, or privacy wall.
Round Fire Pit
On the other hand, rounded fire pits are less structured and formal; they invite talk between guests thanks to zero corners and circular seating.
Don’t forget that because it’s in the shape of a circle, round fire pits best mimic a traditional campfire and provide the same amount of heat towards each guest seated nearby.