Building An Outdoor Fire Pit With River Rocks

We regularly hear the question “Can I build a fire pit with river rocks?”  Who wouldn’t want to construct something out of the beautiful stones they find near bodies of water? Stones carved and smoothed by the passage of time and millions of gallons of running water make for beautiful scenery. But just because you can do something and just because it would look good doesn’t mean you should. In fact, here are some reasons why you shouldn’t build an outdoor fire pit with river rocks (and instead buy a professionally made fire pit).

Beautiful River Rocks

River Rocks May Explode Under Heat

River rocks are not like the kind of stones found at your local home improvement stores. Some aren’t porous and have air trapped in them. When placed around a burning fire, that air subsequently heats up. If we think back to middle school science class, we’ll remember that when air heats up, it expands. This can put an immense amount of pressure on the river rock leading to an explosion.

Don’t believe me? Our ancestors frequently counted on this happening in order to break up rocks. “Fire-setting” was an ancient form of mining and was a good way to split stones before the advent of modern machinery. Here is a YouTube video showing the practice:

It May Be Illegal To Collect River Rocks

If exploding rocks wasn’t enough to convince you, there is also a question of legality with collecting river rocks. In state / federal parks, it’s often illegal to take any natural resources. And if you’re trying to find the rocks on private land, you really need to make sure you have permission to be there. Trespassing laws vary from location to location but can certainly lead to a bad time!


I’m not one to tell people what to do, but making a wood burning fire pit out of river rocks isn’t a good idea. Especially when great, professionally made fire pits are available for purchase on the internet. However, if I still haven’t talked you out of it, at least be careful when obtaining the river rocks and building your fire pit. And if your fire pit decides to explode, don’t say I didn’t tell you!

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