# Lava rock help....

Discussion in 'Landscape Maintenance' started by Greg78, May 4, 2011.

1. ### Greg78LawnSite Silver Memberfrom Southwest, FLPosts: 2,010

I got a customer wants some lava rock put down... even though I hate the stuff.
I need to cover 130 square feet at 2 inches thick. I know how to calculate mulch, not sure how to calculate rock?
I was looking at getting some .5 cu ft bags and doing it with them. The bag says it covers 6 square feet (doesn't say how deep) so I would need approximately 22 bags.
I've read that lava rock will cover 180 square feet per ton at 3" deep. Using that it seems like I would need more than 22 bags (484 lbs) even at 2" instead of 3"?
Need some help here?

2. ### Darryl GLawnSite Fanaticfrom ConnecticutPosts: 8,041

It's the exact same calculation no matter what the material is. Just take the 130 sq feet and multiply by 0.1666 feet thick (2 inches divided by 12 inches per foot). So you need 21.7 cubic feet. Divide that by 0.5 (or multiply by 2 bags per cubic foot) and you need 43 bag to get a depth of 2 inches. It looks like they're only figuring on 1 inch thick with the coverage they give.

3. ### Greg78LawnSite Silver Memberfrom Southwest, FLPosts: 2,010

Thanks Darryl.

4. ### Landscape PoetLawnSite Gold Memberfrom Oviedo/OrlandoPosts: 3,638

Yep, but Greg, most of the Lava Rock Bags also already give you the break down on them of what kind of coverage they provide. If given proper coverage, and proper markup you should make a small fortune off doing this for the client. And another nice sum of money down the line when our sandy soil "eats" most of the rock, and even more when they decide they do not like it as it sinks into the ground, and you have to explain to them that you will be removing it for a long time cause it is sunken in about 6 to 8 inches in the ground.

5. ### Darryl GLawnSite Fanaticfrom ConnecticutPosts: 8,041

You're welcome

6. ### Dr.NewEarthLawnSite Bronze Memberfrom Vancouver CanadaPosts: 1,441

Do you use a landscape fabric under your lava rocks?

7. ### Florida GardenerLawnSite Fanaticfrom Humid S. Fl. with sights set on San DiegoPosts: 6,288

i dont like the red lava, but the black lava rock is sick imo.....

8. ### Landscape PoetLawnSite Gold Memberfrom Oviedo/OrlandoPosts: 3,638

Just wondering, how do the plants like the radiant heat given off by the BLACK lava? That has to be a pretty damn got bed during our summers....do plants not just sit there and sizzle like bacon?

9. ### Florida GardenerLawnSite Fanaticfrom Humid S. Fl. with sights set on San DiegoPosts: 6,288

I dont like it with plants, but as a decorative feature in walkways and what not. I prefer to mulch plant beds as the mulch breaks down over time and adds to the soil. Plus, if you ever have to remove rock, it is a PITA.

Another really nice rock is the mexican beach pebble....

10. ### GroomerLawnSite Bronze Memberfrom mow countryPosts: 1,421

lava rock belongs, well, where it came from? or maybe the grill.