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Are Lava Rocks Good For Fire Pits?

We’ve always burned logs in our fire pit, but our neighbors swear by lava rocks. Perhaps it’s time to give them a try, but are they any good?

Lava rocks are good for fire pits as they disperse the flames, spread the heat and look great when burning. They can withstand very high temperatures without cracking or exploding (if burnt from dry), and can also retain heat for several hours which makes them ideal for all types of fire pits.

Let’s dive down into the subject of lava rocks in more detail, and discover how and why to use them in our fire pits

Are Lava Rocks Good For Fire Pits?

What Does Lava Rock Do For a Fire Pit?

Lava rocks work well in a fire pit because they disperse the flames, spreading the heat and giving the pit an appealing look. Heat coming from the burner goes straight upwards, but if you add a layer of lava rocks to the fire pit, the heat will spread out around the burner.

Because the heat is now radiated through the hot rocks, you’ll get that lovely campfire feel when you sit around the fire pit. Not only that, if you have a gas fire pit, it’ll look far more realistic, too.

Can You Use Lava Rocks in a Wood Burning Fire Pit?

Yes, you can use lava rocks in your wood-burning fire pit. They help to disperse the heat, and create a protective bottom layer for the pit. They also protect the fire pit from hot spots, which can ultimately lead to cracking. 

Put a thick layer of lava rocks on the base of the fire pit: about four or five inches from the top is ideal. Make sure that water can still drain through. You can then add the logs on top of the lava rocks, and enjoy an even warmth from the fire pit.

Can You Use Lava Rocks in a Propane Fire Pit?

Lava rocks are ideal for propane fire pits, as they can withstand super-high temperatures. They are also helpful in other ways, distributing the heat evenly. 

As well as creating a pleasant warmth for everyone around the fire, this also prevents hot and cold spots from developing, which can damage the fabric of the fire pit. Lava rocks help to create a drainage layer at the bottom of the pit, as well as insulating the gas burner from extreme heat.

Do Lava Rocks Hold Heat?

Lava rocks are great at retaining heat, and they create a lovely, even warmth. You’ll need to leave them to cool for at least an hour after switching off the flame, if you need to move or cover them.

Is Lava Rock Fire Proof?

Well, it was formed by volcanic magma… Lava rock can stand extremely high temperatures, which is why they’re perfect for fire pits. Other rocks can crack or even explode at high temperatures, but lava rock just calmly carries on retaining heat. 

How Long Do Lava Rocks Last in a Fire Pit?

Lava rocks should last for around two years before they start to show signs of wear. Keep using them in your fire pit until you notice them getting a little crumbly looking. There are a couple of ways to extend their life: try not to move them around too much (they’ll scrape against each other), and don’t let them stay wet for too long.

What Can I Do With Old Lava Rocks?

We have a couple of great uses for old lava rocks in our yard. They can be used at the base of planters to create that essential drainage layer. So, it’s definitely worth hanging onto at least a few lumps of old lava, and keeping them in your shed ready for your next planting session.

You can also mix them up with soil to create a mulch. Because it doesn’t decompose like most mulch materials, it’s clean and long-lasting. Its porous texture apparently also makes it good for regulating the soil’s temperature.

Where Do Lava Rocks Go in a Fire Pit?

Lava pits go on the base of the fire pit. Many users put a layer of pea gravel or sand down first, then lay the lava rock on top of this. How deep this layer should be depends on the individual fire pit (anywhere between two and five inches).

How Deep Should Lava Rock Be in a Fire Pit? (How Much Do I Need?)

This depends on the particular fire pit, so you’ll need to check the instructions for your model. It could be anywhere between two and five inches. You can pick it up by the sackload from places like Lowe’s and Home Depot.

What Happens if Lava Rocks Get Wet?

Lava rocks can get wet: but you’ll need to make sure they’re dry again before using them on your fire pit as they can explode. Yes, that’s a pretty dramatic answer to the question; however, you can prevent this from happening by simply not heating wet lava.

Why do lava rocks explode? Lava is a porous rock with lots of tiny holes, like a sponge. Water gets inside, and when it’s heated up, steam forms. This steam causes the rock to expand and, well, pop.

You can prevent this by protecting your fire pit from the rain, and by drying out any wet rocks before you light the burner. You can dry them out by putting the burner on low for up to half an hour, letting the heat dry them out in a controlled way (kids and pets need to be kept indoors while the wet rocks “cure”).

Why Are The Lava Rocks Popping in My Fire Pit?

The lava rocks are popping because they have water trapped inside them. Water enters the porous rocks through the tiny holes, and when the rocks become hot, this water turns to steam. The pressure caused by the steam leads to the rocks exploding.

If you hear a pop, don’t panic. Simply make sure everyone moves back from the fire pit until the popping stops. If the rocks are wet, it should take about 15 to 20 minutes for them to “cure” (dry out). Don’t attempt to remove a popping rock. Just keep your distance until the fire pit has dried out.

Lava rocks in fire pits
You can use lava rocks in a stone fire pit

Can You Roast Marshmallows Over Lava Rocks?

Lava rocks are perfectly safe to cook over, which is why you see them featured in so many gas BBQs and grills. Sitting round the fire pit on a dry evening in the Fall, roasting marshmallows… Perfect.

How Do You Start a Fire Pit With Lava Rocks?

Follow these simple guidelines to start up your fire pit with lava rocks…

If you have a fire pit with a push-button ignition, start by removing the rocks around the burner. Open the gas valve slightly (check the manufacturer’s guidelines) then press and hold the ignition button. The spark from this will light the fire. Safely rearrange the lava rocks around the burner, and adjust the flame using the valve.

If you don’t have push-button ignition, you’ll need a long match. Again, remove the rocks and open the gas valve a little bit. Light it with the match, then you can control the flames using the valve. Safely move the rocks around to cover the burner.

Do You Cover The Burner With Lava Rocks?

Once the burner is lit, you can move the rocks back over it (using tongs or fireproof gauntlets). The insulating rocks help to protect the burner from the heat of the fire. You’ll also need to make sure that the rest of the rocks are evenly distributed, to get the best effect and the most efficient warmth.

Can I Mix Fire Glass With Lava Rock?

Yes, you can mix fire glass and lava rock in a fire pit, and you’ll get a great effect. The rustic rock and shiny tempered glass complement each other beautifully, and it creates a really aesthetic finish.

 Also, fire glass is more expensive than lava rock, so by diluting it with the cheaper product, you’ll save a few dollars. Just bear in mind that the glass portion will need more regular cleaning than the rocks will.

Final Words (& Video): Which is Better Lava Rock or Fire Glass?

Both are good at distributing heat, and they also both look fabulous in a fire pit. Fire glass comes in a choice of finishes, and is great for creating a fashionable, contemporary look. Lava rock also looks lovely, especially if you want a more rustic effect.

If there’s a good chance your fire pit will keep getting wet, fire glass is an easier option. Wet lava rock can explode when the water trapped inside it turns to steam, so you’ll need to spend time drying it out. Wet glass doesn’t have this issue (although you will need to clean it more to keep it looking sparkly). 

However, fire glass can cost up to four times the amount of lava rock, so if you want to stick to a budget, lava rock is the better option. If cost isn’t the concern, simply choose which one you like the look of the best. Need help deciding? Take a look at this short film about lava rocks and fire glass.

Mark H.

Homeowner and property investor Mark H. aspires to bring you the very best outdoor living content, based on his years of experience managing outside spaces. Read more >