Cubic yards, tons, and coverage for lava rock projects. Enter your area dimensions and depth.
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Lava rock is volcanic stone — porous, lightweight, and distinctively textured. It weighs roughly 1,500 lb per cubic yard, nearly half the weight of river rock or crushed granite. That lighter weight means more coverage per ton and lower delivery costs. Lava rock is available in red, black, and brown, and it doesn't decompose, fade, or attract insects.
Lava rock weighs approximately 55 lb per cubic foot, or about 1,485 lb (0.75 tons) per cubic yard. Compare that to river rock at 100 lb/cu ft (2,700 lb/yd) — lava rock is 45% lighter. This makes it easier to spread by hand and cheaper to deliver per square foot of coverage.
Lava rock excels in hot, dry climates — it retains soil moisture, doesn't decompose, and provides excellent drainage. It's popular in xeriscaping (low-water landscaping). Drawbacks: rough texture, porous surface can trap debris, and it's harder to clean than smooth stone. It's not recommended for play areas or anywhere people walk barefoot.
Lava rock's light weight is its biggest advantage for both coverage per dollar and ease of installation. One pickup truck load of lava rock covers significantly more area than the same weight of conventional stone. The downside: lava rock's porous surface can be rough on bare feet and it's harder to rake or blow leaves out of compared to smooth river rock. Best suited for beds, borders, and areas where you won't walk barefoot.