# how to figure out how much rock to order



## Bondo (Dec 8, 2007)

Ayuh,... Ordering stone isn't an Exact science...
The way ya did it is pretty much how it's done...
If ya think you might be short, just guesstimate how much extra ya need...


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## fabnavigator (Jun 3, 2011)

Hi,

I was wondering the same thing. I calculate that I need 10 years of crusher run for my project. Should I get an extra 10%, or as much as 20% more? Any suggestions? I don't want to run short, but I don't want to end up with yards too much

Regards,

Bill


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## bob22 (May 28, 2008)

Might try this site's calculator as it seems to account for density:
http://www.graniterock.com/how-to_theater/construction_calculators/
I've no idea if it works or what the appropriate density should be or what can be achieved with hand tamping and the material you are compacting.


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## Daniel Holzman (Mar 10, 2009)

You are correct in assuming that a cubic yard delivered in the truck is a larger volume than the same material in place. Aggregate (sand, gravel, stone) ranges in density from loose to dense, depending on whether it has been compacted. The variation can be as much as 30 percent, meaning that 100 cubic feet of sand in the loosest condition may compact to as little as 70 cubic feet if you apply maximum compaction effort.

The actual amount of compaction you get depends on how loose the aggregate is to begin with, the type of compaction tool you use, the amount of time and effort you apply, and the moisture content of the aggregate during compaction. But this is all needlessly technical, a good rule of thumb is to buy 20 percent more than you need, you can always find something to do with a small amount of extra material if you don't use it all.

By the way, the 20 percent rule of thumb does not apply to peat moss and organic soil, which can be compacted far more than sand and gravel.


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## DexterII (Jul 14, 2010)

Another factor, which can go either way, is that while you are measuring with a tape measure, your supplier is measuring with a loader bucket, and/or the box on the truck, and an inch or two higher or lower in the box, even on a "standard size" dump, can make a fair amount of difference. So, while a cubic yard has a defined size, by the time it gets to you, as Bondo says, it is not an exact science.


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## fabnavigator (Jun 3, 2011)

Thank you for your help.

My calculations say I need 10.25 yards. I'm going to assume that when I put down 2 inches, I'll end up with 1.5 inches after compaction. That means that I need 13.6 yards. I'll round that up to 14 yards. I'll probably have way too much, but that is the lesser evil.

I think I'll pay an extra delivery charge, and have it brought in two 7 yard loads. I don't want to damage my asphalt driveway.

I'm going to do this next weekend. I'll post the results.


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## fabnavigator (Jun 3, 2011)

I completed the base installation last weekend.

I'm glad I ordered all 14 yards. I probably had about a yard extra, but I wouldn't have wanted to try and use every last bit. I used a skid loader to move the gravel from the pile to my walkway, and since I didn't want to scrape the bucket on my driveway, I had to leave a thin layer behind.

The gravel came in two loads, from two different places. One had a good moisture content, the other was dry. It took a fair deal of extra work to add enough moisture to the dry gravel in order to get good compaction.

I got from 3/8" to 1/2" of compaction out of a 2" spread layer of gravel.

There was no problen with driving the truck (with 10.5 tons of gravel per load) over my asphalt driveway.


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