# Estimating rock?

Discussion in 'Landscape Maintenance' started by lkendall, Apr 19, 2012.

1. ### lkendallLawnSite Memberfrom Ocean City, MarylandPosts: 157

Got a drainage job the other day.. The ditch is 150' long x 5' deep. They only want one side, which is the side they own . They want it cleared out, drain cloth, and river rock on top. The closest rock delivery place which is about a mile away only sells by the ton, which makes for rough estimating. The rocks are 5-8". If anyone could help me out with this that would be great!

2. ### lkendallLawnSite Memberfrom Ocean City, MarylandPosts: 157

Ive found that one place says 1 ton of 4-8" cobble 4-8" depth = 45 sq ft..

3. ### skbandLawnSite Memberfrom Dawsonville, GaPosts: 1

I'm new to the forums (Hi Everyone).

Google is a wonderful place to find answers. This is what I located kinda in line with what you found.

Here is a variation on how deep the coverage will be.

River Rock weighs 2,800 LBS. per cubic yard - That's 1.4 tons per cubic yard.

One ton = 2,000 LBS. 2,000 divided by 2,800 equals roughly 0.71. So one ton of river rock is roughly 0.71 cubic yards.

0.71 cubic yards covers roughly 230 square feet 1" deep
0.71 cubic yards covers roughly 115 square feet 2" deep
0.71 cubic yards covers roughly 77 square feet 3" deep
0.71 cubic yards covers roughly 57 square feet 4" deep
0.71 cubic yards covers roughly 38 square feet 5" deep

Hope this helps out.

4. ### AzLawnManLawnSite Senior Memberfrom Glendale, AzPosts: 409

River rock usually covers anywhere between 40-50 sqft. You have 750 sqft feet, so order 15 tons. Or, give the measurements to the rock company, and the will give you the tonnage. Remember, most river rock and rip rap is uassually placed by hand and cannot be spread as easily as 1/2 inch or 3/4 inch, so factor that extra time into your bid. River rock at one location may not be the same size at another location. Also, I have never used a drain cloth so make sure the customer knows that the cloth may be visible because river rock does not set together and does leave voids because it is a larger rock.

5. ### lkendallLawnSite Memberfrom Ocean City, MarylandPosts: 157

Thanks for the info! But I pulled out of the job. The town it was in has about 300 people and the ones in charge are crazy. They wanted to sit down with engineer's and re shape the entire ditch( I was only putting rock on one side) Then they had about 20 other things that they wanted me to do while I was there, and they weren't the ones paying for it. The owners said it was ridiculous and they decided to not do it and just clean it out. Thanks though!