Red lava rock is an inexpensive, aesthetically pleasing material to add color and efficiency to your gas-powered fire pit. Prefabricated or home-built fire pits designed for propane or natural gas can use lava rock for more even, effective heat.
Unlike wood, lava rock can be used over and over and doesn't create smoke or ash. Choosing the right kind of rock and filling the pit correctly are key to being able to enjoy your lava rock fire pit safely.
Never use wet lava rock in a fire pit. Wet rock can explode or fly out of the pit, causing injury. Brand new lava rock may contain a small amount of moisture, causing the rock to "pop" when the fire pit is first lit. Stand well away from the pit until all popping sounds cease.
Lava Rock Options
Lava rock is generally black, grey or red, although variations in color can exist. It can be purchased in a variety of sizes, from crushed gravel sized pieces, to small rocks up to 1 inch in diameter, to large chunks that are 4 inches across or larger.
Lava rock that is 1 to 3 inches in diameter is the most common choice for fire pit use. Only use real lava rock in fire pits, not synthetic versions designed for use in planters or gardens.
Calculating Lava Rock Requirements
How much lava rock you need to purchase will depend on the size of the plate in your fire pit. Most lava rock is sold in bags that contain 1 cubic foot of rock.
To calculate how much you need, measure your plate's diameter. A 24-inch plate will require 1 cubic foot of rock.
For every additional 6 inches in plate diameter, another cubic foot of rock will be required.
Lava Rock Installation and Adjustment
After the burner is in place, the gas connected and the plate positioned, it's time to add the lava rock. Don't pile the rock too thickly or the gas will be unable to sustain a flame through it.
Move the rocks around gently with a poker until the flames take a form you like. When using new rock, stay clear of the fire pit for 20 to 30 minutes after it is lit to allow moisture in the rocks to burn away.
Ceramic Fire Logs
A set of ceramic logs can be placed on top of red lava rock to create a more natural appearance. The lava rocks will allow the gas flames to flicker up around the logs so it appears to be a traditional wood fire.