# estimating formulas

Discussion in 'Hardscaping' started by JJfishes, Apr 21, 2006.

1. ### JJfishesLawnSite Memberfrom Rochester, New YorkMessages: 14

Wondering if anyone knows of a site to get info on estimation of bulk materials needed, specifically base material for patios and walks. An example would be 100 square feet by 9 inches deep of COMPACTED material. How much base material do i need in tons or yards.

Thanks Jay

2. ### BustusLawnSite Memberfrom Ontario, CanadaMessages: 181

I'm not sure they are exactly what your looking for, but there have been posts on this topic. Just use the search function and I'm sure you'll find some formulas. Good Luck!

3. ### DVS HardscaperLawnSite Fanaticfrom County JailMessages: 6,576

I have a feeling you'll receive varied responses.

We have been doing full fledged hardscapin for 10 years. And have always been right on the money with the following formula:

TOTAL SF x inches / 3 / 27 = x 1.2 x 1.5 =

Ok I'll go further:

100 x 9 / 3 / 27 = 11.11 x 1.2 x 1.5 = 20 tons

dividing by 3 is what equates the inches

multiplying by 1.2 is what converts cu yds into tons

multiplying by 1.5 is what accounts for compaction.

This is the only formula I have ever used. (computerized estimating system does it for me), and I do know other folks have other good formulas.

http://www.outdoorfinishes.com

4. ### TECLawnSite Memberfrom Allentown, PAMessages: 2

The way I do is take your SF x base thickness x 10 and divide by 2000
10 represents 10lbs per SF@ 1 inch compacted 2A modified stone

100 SF @ 9" = 100*9*10=/2000= 4.5 Tons

a 10X10 pad & 20 ton would equal a 40" base

5. ### cglandLawnSite Bronze Memberfrom Reading, PAMessages: 1,929

Andrew - Instead of dividing by 3 you should be dividing by 12. 20 tons for a 100 sq. ft. patio @ 9"! That's crazy! I came up with 5 tons or 4.99999 to be exact.

Chris

6. ### bigviclbiLawnSite Senior Memberfrom njMessages: 900

I'd be about 5 tons for 9" but I'd have to say it varies depending upon what you are using as your base.

7. ### Mike33LawnSite Bronze Memberfrom Cumberland, MarylandMessages: 1,649

This is really funny we get all different answers. I got 4.9 tons but with price of fuel of going back for a small quanity i would get 6 ton. I use sq.' divide by 27 multiply by 1.35 Was wonering how the 1 guy got 20 ton?

Mike

8. ### cglandLawnSite Bronze Memberfrom Reading, PAMessages: 1,929

Mike - The price of fuel in no way affects the tonnage needed to cover that excavation!

Chris

9. ### Mike33LawnSite Bronze Memberfrom Cumberland, MarylandMessages: 1,649

My point was formula was 5 ton. I would for this size job get a extra ton because of fuel prices i would not want to be a litttle short and where i have to go to get stone the fuel and time would hurt. You do have to look at your time and fuel these days you can always take a half ton away cheaper than holding the job up.

mike

10. ### mruskLawnSite Gold Memberfrom northern jerseyMessages: 3,260

I always over order base material. 90% of the time there is somewhere to dispose of it on site, since i don't have a dump truck.

Sometimes the customer gets real happy when i spend 5 minutes and fill in some pot holes on there driveway.