Can fire pit rocks explode? - MAX Fire Pits (2024)

FAQs

What rocks should you not use in a fire pit? ›

What rocks to avoid? To mitigate this risk, it's crucial to know which rocks to avoid. Porous rocks, including limestone, sandstone, pumice, and shale, are notorious for absorbing water and should be avoided in your campfire. River rocks, often rounded from years of water erosion, are remarkably deceptive.

Concrete blocks, pea gravel, river rocks and other materials that are often used in DIY fire pits can trap water inside. When they are heated up, this can cause an explosion. Here's a demonstration of what can happen when the building materials hold a little too much water and pressure builds up inside.

Special Note: Even lava rock can explode when heated due to moisture getting trapped inside. Make sure to use caution the first time you use your fire pit after rain or when you first install it.

With an outdoor fireplace, there will be fewer concerns about the heat getting too high or too low or even a fire accident that would directly affect the house. Outdoor fire pits with stones are the safest.

Not all rocks are suitable for use in a fire pit, so make sure you check the type of stone before using it. Porous or wet stone, such as sandstone or river rocks, may crack or explode when they reach high temperatures. Hard rocks like granite, marble or slate are suitable for use in fire pits.

We typically use ¾” clean crushed limestone for the gravel fire pit patios we build. We recommend crushed limestone around fire pits because of its excellent drainage. Plus, it compacts well, giving a solid base for seating and other heavy items.

The wrong bricks can explode, and the wrong mortar can cause the fire pit to crumble and fall apart. This is why it is imperative to use kiln-fired bricks and fireplace mortar.

How Moisture Causes Fires to Pop and Crackle. In addition to low combustion efficiency, trapped moisture can cause fires to pop and crackle. Even if a piece of firewood looks dry, it probably has moisture inside its pores. After all, trees absorb water to grow and survive.

While many stones are very resistant to heat, the most important thing to be aware of is that they're not 100% heat-proof, and under the right conditions, stone can crack in extreme heat. This occurs when natural stone is exposed to very high heat in a short period of time.

The glass pieces are non-toxic and will not leave behind any ash or soot, which is great for keeping the outdoor area clean. Lava rocks, on the other hand, are known for being very porous and light. Due to the porous texture, they contain no moisture – and do not hold any heat in.

Why put lava rock in bottom of fire pit? ›

Notably, lava rocks have a very porous texture, which implies that: They contain no moisture. They don't hold any heat in, allowing the flames to heat you. They allow more airflow to your burner.

Lava rocks are low maintenance and last for 3+ years depending on how often you use your fire pit. However, regularly moving lava rock around can shorten its life span as it may cause it break into smaller pieces.

Crushed Limestone

It is often used as the primary material for the fire pit patio itself, creating a sturdy and functional surface. However, it's important to note that crushed limestone should not be used inside the fire pit itself, as it can be an explosion hazard.

A good rule of thumb is to make an above-ground fire pit 12-14 inches tall. This is a few inches shorter than standard patio furniture seat height. If you want to be able to sit on the edge of the pit itself go a bit higher, 18-20 inches will be comfortable.

A cover not only extends the longevity of your fire pit but also saves you time and money. The weather can take a toll on your fire pit in many ways, from water and sun damage to your fire pit filling with debris.

Crucially, don't ever use river rocks. There are several reasons why you should never use river rocks for a campfire, with one of the most obvious being that they are often more porous and can contain water. When this water gets hot it creates steam and the rapid expansion can cause the rock to explode.

Soapstone Hot Rocks are the best alternative to Lava Stone and Glass. They're designed to be used in every type of gas fireplace, grill, fire pit, and BBQ.