Fire-pit depth really depends on what you want and how into your project you’re going to get. For instance, if you just want a basic fire pit, dig about 6 to 8 inches down and call it good. You can go deeper if you want, but keep in mind that you don’t want the hole so deep you can’t enjoy watching the fire. Some people like to add about 4 to 6 inches of pea gravel or sand to their fire pit, as this helps with overall drainage. Of course, this would then require a slightly deeper hole.As to those retaining wall blocks you’re thinking of: It would be better to go with firebrick, something that is made to withstand extremely high heat. If you were just placing the retaining wall blocks around the rim of the pit, they’d serve the purpose well enough, but lining the pit with those types of blocks might one day result in you being clobbered by flying pieces of hot concrete.See alsoMaking a Fire Ring

Are Backyard Fire Pits Safe And Legal ?

We’ve all heard the saying about what happens if you play with fire. So, it’s only natural that you would wonder how safe fire pits really are.

Backyard fire pits can be a safe feature for your outdoor space if you take certain precautions. Here are some ways to ensure your fire pit is safe:

  • Keep fire pits at least 15 feet away from your house, other structures and combustible materials (ex. leaves, wood, chemicals, etc.). It should be in an open space, like on your patio or a cleared part of your landscape. Don’t put it on a wood deck.
  • Avoid lighting the pit during extremely windy weather, as the embers might go somewhere you don’t want them.
  • Make sure you have a bucket of water, hose or extinguisher nearby before lighting the fire.
  • Watch children near fire pits so they don’t get burned.
  • Keep the flame small: The larger it is, the bigger chance you have for it to get out of hand.
  • Never use gasoline to start the fire.

Beyond being safe, you also want to make sure your fire pit is legal. The city of Idaho Falls allows fire pits and other enclosed outdoor fire features (ex. fireplaces) that are at least 15 feet away from structures and combustible material. They also require that they are used in accordance with the manufacturer’s instructions.

(Each city’s fire and burning codes are different, so check with your local municipality before you install a fire feature.)


4. Fill Your Pit With The Right Materials

Learning what to put in the bottom of your fire pit takes more planning than you may have considered. Some materials like hard rock, gravel, or sand weren’t meant to reach high temperatures and can spark and explode if your fire gets too hot. Instead, use lava rocks for your fire pit or lava glass beads as a filler for your fire pit. They are a safe way to create drainage and make your fire pit look nice. While some people choose to forgo a fire pit filler and simply use a concrete or stone base, filler adds a nice aesthetic to your fire pit that can enhance your backyard landscaping. Place a thin layer of sand on the bottom of the fire pit and add the recommended 2-6 inches of filler on top of it. If you don’t have a preference for what kind of filler to use, irregular crushed lava rock or small volcanic ash tends to cost less overall. Sandstone, river rocks, natural rocks, and gravel are not ideal fill for fire pits because they are more likely to crack or explode under high heat. No matter what type of fill you use, make sure the fill is dry when you light the fire. Rocks can absorb a lot of water, especially river rocks, and rocks that get too hot near a fire can (and sometimes do) explode. Even wet lava rock can explode.

Fire Pit Parts: An Overview

Illustration by Gregory Nemec

A built-in fire pit is a glorified campfire, with sturdy walls of stone that help contain the flames and heat. That’s especially important in the parts of the country where there’s a risk of brush fires. So the first task in building any fire pit is checking local codes on open flames. The pit must be located far from overhanging trees, the house, and any other flammable structure.

To make building stone walls easier, you can use blocks made from cast concrete and molded to look like real stone (available at any home center). They’re flat on the top and bottom so they stack neatly, and some interlock for added strength. Glue them together with masonry adhesive. Choose a block with angled sides, meant to form curves when butted against each other. The optimal size for a fire pit is between 36 and 44 inches inside diameter. That will create enough room for a healthy fire but still keep gatherers close enough to chat.

As an added precaution, the fire pit should be lined with a thick steel ring like the ones used for park campfires. These protect the concrete in the blocks from the heat, which can cause them to dry out and break down prematurely.

A fire pit should sit low to the ground, with walls rising no more than a foot off the ground. But for stability, the base of the wall must be buried below ground in a hole lined with gravel, providing drainage and protecting against frost heaves in winter. The gravel also creates a level base for the stones to rest on. Most concrete blocks are about 4 inches high, so if the first course and a half sit underground, and there are two and a half courses above ground with a cap on top, you’ll end up with a foot-high wall—just right for resting your feet on while sitting in an outdoor chair.

12. Get That Added Value

Save all the hassle with Portofino® Comfort Stone Top Fire Table – Espresso

A beautiful, well-built fire pit adds a lot of value to a home and backyard. Patios with a fire pit are especially valuable because they create a beautiful space for entertaining and visiting with guests – especially if that space is not available inside the home. Fire pits remain popular with home buyers and really don’t cost much for the value they add. To get the most value from your fire pit, make it a central feature of your backyard and invest in quality landscaping and outdoor furniture, that adds to the overall design of your space. There are even stand-alone fire tables and fire table and chair sets that create a quick and easy focal point if you prefer a more temporary option. If you want your outdoor space to feel like an extension of your indoor space, make sure to use similar design elements as you make the transition from inside to outside. It will make your home feel larger, especially when entertaining guests.

Set the Face Brick

  • To keep your mortar joints between courses a reasonable width, lay a 2-3-in. thick bed of mortar right on top of the footing.
  • Let it set up slightly (give it at least 15 minutes) and smooth out the top.

In-Ground Vs. Portable Fire Pits

When deciding between installing in-ground and portable fire pits, think about the differences in the two and which fits your lifestyle best.

For a more permanent, out-of-sight feature, try an in-ground fire pit. These will give you that bonfire-type look and feel, and they could even be covered up if needed. If you have children, just make sure they can’t fall into the pit if you go the in-ground route.

A portable fire pit gives you more versatility, which is great if you have trouble making decisions about exactly where you want the pit to go. Having a fire pit that is higher up will help the heat better reach you when you’re sitting or standing near it. A fire pit above ground will also help give your landscape a focal point and create visual interest. Your landscape needs at least one thing that draws people’s eyes, and a portable fire pit could be it.

Fire Pit Distance From House, Property Line, and Other Structures

  • The first rule of thumb as far as placing your fire pit is to make sure it is a safe distance from the building and other structures and items that are flammable. This includes your house, sheds, fences, bushes, trees, and shrubs. Make sure to check the specifics on how far away from the house a fire pit should be in your area. This also reduced issues with wind direction pushing toxic fumes your way.

  • Most places require a clearance above the fire pit of 21 feet, to allow for overhead branches.

  • Be mindful of your property line. Many places have restrictions on how close a fire pit is allowed to be to the border of your property. The distance varies depending on your county or municipality, so be sure to check out the specifics where you live.

  • Avoid placing your fire pit on uneven ground.

  • Make sure you are not placing your fire pit underneath any power lines.

Operation Guidelines

  • One of the most important things you can do when prepping your fire pit area is removing any combustible materials from around the pit. Any mulch, brush, leaves, and pine needles should be removed. You can collect it and use it in your fire as a starter or kindling to get things going. Many local laws say the distance that needs to be cleaned around the pit is anywhere between 15 and 25 feet.

  • There should always be a responsible adult tending to the fire until it has been extinguished completely.

  • Many local laws say that you must have a mesh screen cover handy to contain any sparks and embers that may get out of control.

  • You must keep fire suppression equipment close enough that it can be used immediately if the fire should start to become a problem. Acceptable items would be a fire extinguisher, garden hose, water buckets, and sand.

  • You must keep the fire in outdoor fire pits to a reasonable and controllable size.

  • Keep a bucket of sand nearby to help in an emergency, or if windy conditions increase.

  • The only firewood allowed is dry, clean, and seasoned firewood; no lighter fluid or other flammable materials may be used.

Do Not Burn:

  • Wood products that contain glue or resin

  • Garbage, including food waste

  • Treated or unpainted wood, like materials from wood decks.

  • Unseasoned or wet wood

  • Animal carcasses

  • Yard waste

  • Construction material

  • Anything that will release toxic emissions, strong odors, or dense smoke when burned

  • Materials that contain grease, plastic, asphalt, paint, rubber.

FAQ About Building a Fire Pit

What do you put in the bottom of a fire pit?

You’ll want to start with a layer of sand at the bottom of the pit, and then top the sand with gravel, lava rocks, fire pit glass, paving stones or even bricks for your fire pit. Alternatively, you can simply use dirt.

How do you prepare the ground for a fire pit?

Clear away all grass and plant material. Excavate about 8 inches of soil, ensuring that the bottom of the pit is level and the soil is compact.

Can you build a fire pit on dirt?

Yes, you can build a fire pit on dirt. Make sure the dirt is compact and level.

What is the best base for a fire pit?

You have several options. Plain dirt is fine, but sand topped with gravel makes a more attractive base.

Accounting for Height in Fire Pit Design

The height and the circumference of your fire pit are critical details that should also be given attention. It’s not uncommon for do-it-yourselfers or even landscapers that haven’t built a lot of fire pits to build them too high.

This is typically an effort to make the fire pit safer by preventing logs or embers from rolling out and keeping the fire contained. However, what ends up happening is that the kids need to lean over to roast their marshmallows—in actuality making the higher fire pit less safe.

In general, a good height for the outside edge is between 6 and 12 inches tall. This is enough of a safety buffer to keep logs from rolling out but it’s not too deep that there is a need to “lean in” to get close to the fire.Finished DIY Fire Pit

Finished DIY Fire Pit

  • Give the cement and mortar a week to cure completely before lighting a fire in your pit.
  • Pour a few inches of gravel on the pit’s floor for drainage and you’re ready for your first wienie roast.



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