If you have (or would like to have) an outdoor fire pit to sit and cook by, you may be wondering whether to use some lava rocks in there.
You’ve probably already heard a lot of good things about them. They spread the heat really well by dispersing the flames.
They can handle high levels of heat without exploding or cracking, provided they are dry.
And they retain heat for hour upon hour, which is perfect for when you want to stay out all night under the stars by the warmth of the fire pit.
But before you go ahead and order some lava rocks, it’s best to familiarize yourself with the ins and outs of them so that you know what to expect and how best to use them.
And to that end, we’ve put together this long FAQ article, answering any and all of your most frequently asked questions on the subject.
Please feel free to scroll ahead to any section that jumps out at you. Here goes!
Let’s kick things off with the basics…
We mentioned this earlier, but it bears repeating here. The great thing about putting lava rocks in a fire pit is how they disperse the flames, thus causing the heat to spread around the burner, rather than just straight up as they otherwise would.
And it looks amazing. With the heat radiating through the rocks, you get that warm campfire feel that everyone loves. And it looks particularly stunning on a gas fire pit, looking super realistic.
Since lava is created from actual volcanic lava, we know that it can sustain extreme high temperatures.
Whereas regular rocks are prone to crack, or worse explode, at high heats, a lava rock will simply sit there quietly enjoying the heat along with you.
Lava rocks can retain heat incredibly well, while still giving off plenty of heat and warmth.
For this reason, you need to be particularly careful handling them. If you want to remove the rocks from the pit once the fire is out, you should wait for them to cool for a minimum of an hour before handling them.
I am pleased to confirm not only that you can use lava rocks on a wood burning fire pit, but also that it’s recommended.
In addition to dispersing the heat and making the campfire look more attractive, lava rocks can protect the bottom of the fire pit from the hot spots that can, unfortunately, induce cracking.
Here’s what you should do:
Place a layer of lava rocks on the fire pit’s base, ideally approx 4 to 5 inches from the top, in such a way as to ensure that water is able to drain through.
Then add your wood logs on top of the rocks, and sit back and enjoy a more even warmth.
Again, I’m pleased to say that the answer is Yes, you sure can use lava rocks on your propane fire pit, thanks to their ability to survive extreme temperatures.
What’s more, using them will help to distribute the heat more evenly, and prevent hot spots and cold spots from forming, which could cause damage to the fire pit’s fabric in the long term.
When using lava rocks in a fire pit, you should place them on the base. Some people like to put a layer of sand or pea gravel first, before the lava rocks though, and this is fine.
You may also be interested in the answer to the next question…
How deep your layers of lava rock should be, depends entirely on your particular fire pit. If you still have the instructions for the specific model of your fire pit, you will find the best guidance there.
You will usually need your layer of lava rocks to be at least two inches deep, but this could stretch to up to 5 inches. Luckily, you can pick lava rocks up by the sack load from stores like Home Depot and Lowe’s.
Again, here, you should check the instructions that came with your model of fire pit. Some burners are meant to be fully covered with lava rock, and some do not. If you have a crossfire burner with jets, these jets need to be left exposed.
Lava rocks can insulate the burner from the heat of the fire. You can use tools to move the rocks on the burner once it’s lit if you need to (just be careful).
The key thing is to ensure that the lava rocks are evenly distributed.
You won’t believe how long lava rocks last - you can continue to use them up to a whopping two years before they show any signs of wear.
You only need to remove them from the fire pit if they start to look kinda crumbly.
If you want to extend the lifespan of your lava rocks even further, simply avoid moving them around more than necessary.
This is because they are prone to scrape each other. And if they do get wet, try to dry them out as soon as possible afterwards.
Here’s a quick step-by-step guide to starting a gas fire pit with lava rocks:
First off, don’t worry. Popping lava rocks on your fire pit aren’t anything to worry about, there’s a simple explanation for it…
Here’s what’s going on, water has got into porous holes in the rocks, and when this water gets hot, it becomes steam. As the steam heats up and expands, it will cause the lava rocks to pop.
All you have to do is get everyone to step back from the pit until the popping has come to a stop. And they won’t have to step back for long - you only need to wait a maximum of 20 mins for the lava rocks to dry out if they are wet.
The important thing to remember is that you should not try to remove a lava rock when it’s still popping, Instead you should keep away until the steam has all gone and the pit has completely dried the lava rocks out.
I am pleased to confirm that it’s perfectly safe to roast marshmallows, and other foods, over lava rocks. In fact, you will often see lava rocks featured in gas barbecues.
So by all means go ahead and enjoy gooey marshmallows toasted over your lava rock fire pit!
If your lava rocks get wet from the rain, it’s not the end of the world.
However, you HAVE to ensure that they are 100% dry before you use them again, since any steam that builds up within the holes of the lava rocks will cause them to pop once they build in heat.
Ideally, you should use a cover for your fire pit, so that the lava rocks don’t get wet in the first place. This way, you’ll never have to wait around for them to dry out again, so you can light the fire.
You can dry the lava rocks out on the burner set to low if you need to. But if you do this, please ensure everyone keeps away from the pit until the lava rocks are 100% dry. This should take about half an hour.
You certainly can combine lava rocks and fire glass in your fire pit, and if you have the budget for it, it’s highly recommended - the fire glass with its beautiful sheen really compliments the rustic look of the lava rocks, creating a stunning aesthetic.
Side note - it works out much cheaper to use a mix of fire glass with lava rock, than to use only fire glass alone. If you do wish to use tempered glass, remember that they will require more frequent cleaning.
To be perfectly honest, both lava rock and fire glass have their pros and cons. Some people prefer the rustic aesthetic of lava rocks, while others prefer the gleam of fire glass.
If you don’t have a cover for your fire pit, and it’s at risk of getting rained on, fire glass would be better because lava rocks are known to explode with steam.
But on the other hand, fire glass is way more expensive than lava rocks.
If you have some old lava rocks lying around, it may be worth holding onto them…
There are a couple of uses for old lava rocks, including mixing them up with soil to form a mulch. They’re quite good for regulating the temperature of the soil, thanks to their porous texture.
They’re also good for using as a base for planters, since they offer excellent drainage.
So now you can consider yourself fully informed on the subject. Lava rocks make an excellent addition to your fire pit, but be sure to use the advice provided for your safety.
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