Calculating the Concrete Needed for a Driveway

volume is volume. measure the length of the driveway, the width and depth, make sure that all are in the same unit of measure, for instance feet, (a 4" drive is 1/3 ft)

multiply to find the volume and covert to cubic yards, Generally I round up in volume to the next 0.5 yard and then ADD another half yard for slop, error and some extra.

thanks

take the length times the width in ft. and then the depth in inches and then multiply by .0031 this will give you the cu yard that you will need. exp. 50'L X 8'W X 6" D = 7.44 cu yard.

better still...knows first hand.

Don't forget 27 cubic feet in a cubic yard.

I n a pefect world You should get 81 sq. feet per yard of concrete at 4 inch thickness, but to be on the safe side figure about 75 sq. feet peryard.

oilcan13

Hello ihuston6,

Concrete is one of those building materials where said material is sold as if the volume is perfect but the quantity rarely equals the stated volume. This material is actually calculated by weight of the materials. Not all agregates used weight the same, and not always is the same quantity of coarses and fines in the agregate going to be exactly the same from one batch to another.

Therefore we in the business of placing concrete generally will calculate the quantity as if it is filling a perfectly formed area and then adjust for the imperfections of said area.

Ex: 8'wide X10'long X 6"deep 8X10X.5 = 40 40 cu. ft.

40 cu. ft. / 27 cu. ft. = 1.48 cu.yd.

That is if the form is perfect it will contain 1.48 cu yd.s of material. However you must now adjust for the shortage that will exist due to the losses regarding the weight. That is generally calculated at .03 cu. yd. per yard of material purchased and delivered by a batch truck.

Therefore for this adjustment we would multiply 1.48 X 1.03 and the exact quantity you must order would be 1.5244 cu yds.

However as indicated earlier, the form work is rarely perfect. Somehow they are always just a little larger than intended. If I was ordering concrete to fill this form on grade drive way I would order 2 cubic yards. I would anticipate that if I was using a concrete pump to place this concrete that the extra would be enough to compensate for the hose losses, and it is less expensive to waste a little concrete than pay for a short haul load to complete the work because you under estimated the material quantity needed to compensate for less than perfect form work.

TooMuchFun

you probably want to calculate the compression strength of the concrete.

How much weight you're going to pass through ?

If you want your concrete to reach it's maximum strength only add just enough water to get the stuff out of the truck. If you want it to "NOT" crack, don't put any water in it! Ha Ha!

TMF