Here’s What You Should Put In the Bottom of a Fire Pit

Raise your hand if you want answers to the following questions:

  • What should go in the bottom of my fire pit?
  • Are there any special materials that will provide the best insulation?
  • Are there any steps I should take to protect the fire pit?

If your hand is raised, then you will be happy to know that we’ve got all the answers you’re looking for! This blog post will provide comprehensive answers to each of those questions — and provide many other tips for building your own custom fire pit as well.

What Should Go In the Bottom Of a Fire Pit?

There are tons of materials that you can place in the bottom of a fire pit. But not all of them are as effective as the following five.

1. Gravel

Gravel is a great option for the bottom of your fire pit. Although it’s not the best material for insulation, it’s still an excellent choice to make because its stable nature makes it very difficult to ignite under normal circumstances. Meaning that it’s the safest option you have. Furthermore, it also helps direct flames downward into the surrounding area without allowing them to bounce back up toward you or at nearby objects.

Gravel should be placed about two inches thick throughout the entire base of your fire pit before beginning construction on other layers.

2. Sand

Sand is a great material for the bottom of your fire pit for two reasons:

  1. It provides great insulation.
  2. It is one of the safest options you have because it is unstable. What does that mean? It means if you place any item on top of the sand, it will almost certainly sink into the sand as soon as there is heat or pressure applied to it from above. Furthermore, sand also directs flames down toward whatever objects are in the middle without allowing them to bounce back up at nearby people or things.

Just like gravel, sand should be used sparingly (about one inch thick) throughout the entire base of your fire pit before beginning construction on other layers.

3. Lava Rocks

Lava rocks are one of the best materials for building your fire pit because they offer the best insulation. What’s more, lava rocks will not burn, meaning that there’s no risk whatsoever if something happens to be sitting atop them when you light up your fire pit.

You should use these even more sparingly than gravel and sand. Lay lava rocks throughout the bottom at only about half an inch thick. That way, the material underneath has plenty of room to breathe and spread out without having any pressure put upon it by whatever objects may be resting on top.

4. Fire Pit Glass

Firepit glass is the best option you have for protecting your fire pit, as well as keeping it looking beautiful all year long. What’s more, this material offers an excellent amount of insulation and will not burn even if something were to be placed on top of it while a roaring flame was underneath.

Just keep in mind that because these are made out of glass, they may break over time with continued usage. But don’t worry! Test them first by adding some water into the bottom before placing anything else inside or starting up any fires at all. If there are no cracks after 24 hours then you’re good to go!

5. Stones and Rocks

Stones and rocks are the most popular choice for people who want to build a fire pit that looks like it came straight out of nature. These materials provide great insulation and protect your fire pit from damage if anything were ever to fall on top while there was a flame roaring underneath.

Just keep in mind that you should only place stones or rocks throughout the bottom at about one-inch thick maximum. Otherwise, they may collapse when something is placed atop them — especially during fire usage.

What Steps Should You Take to Protect Your Fire Pit?

The first thing you need to ensure safety is to choose one of the five materials that we just mentioned. Apart from that, here are nine more steps you should take to ensure the safety of your fire pit.

  1. Do not place the fire pit on a wooden deck.
  2. Make sure there are no flammable materials around.
  3. Remove all ash from the fire pit after it has completely burned out and cooled down.
  4. Cover the fire pit with a UV and/or waterproof cover to keep it protected.
  5. If you live in a high-humidity area like on the coast, apply a light coat of any accepted food oil to any exposed metal.
  6. Check your fire pit one day before each usage to look for and repair any early indications of rust.
  7. Store your fire pit either off the ground, undercover, or indoors.
  8. Ensure that your landscaping is safe for burning wood or other items in your fire pit. What landscaping materials should you avoid? You shouldn’t have any dry leaves, branches, grasses, flower beds with bark mulch or gravel, low-growing groundcovers, or any other flammable material within three feet of the fire pit’s perimeter.
  9. Watch the weather forecast before planning a bonfire to make sure that no rain is expected on the day you plan to make a bonfire.


Here’s the bottom line. There are five materials that are ideal for putting in the bottom of a fire pit:

  1. Gravel
  2. Sand
  3. Lava Rocks
  4. Fire Pit Glass
  5. Stones

You can use either one — they all work perfectly fine. No matter which one you choose though, make sure to take the safety steps discussed in this post. They can literally save your house from burning down!


  • Nathan Collins

    Having spent years working in the landscaping industry, Nathan Collins has cultivated a wealth of knowledge about the natural world. He is committed to helping others appreciate the beauty in their backyards, whether it's through identifying rare rocks and minerals or crafting the perfect landscape.

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