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A giant ready-mix concrete truck driving up to your house can be intimidating, but it doesn't have to be if your site is prepared, you have all your tools at hand, and you've ordered the right amount. Dispatchers are quite helpful, but you should know the basics before you call so you don't wind up with more or less than you need.
Steps
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1Calculate the right volume. In the U.S. Concrete is always ordered in cubic yards. First figure out the cubic footage, then convert to yards by dividing by 27. Here's how: multiply the length of your project times the width times the depth (4 in. = . 33 ft.) and divide the total by 27. Using a sidewalk as an example: 60 feet (18.3 m). (long) x 4 feet (1.2 m). (wide) x .33 feet (0.1 m). (deep) = 79.2 cu. ft. ÷ 27 = 2.93 cu. yards.You can also figure your cubic yards by this example: length, times, width, divided by, 12, times, thickness, divided by, 27. using the figures from above example. 60 feet (18.3 m) ( length ), times 4 feet (1.2 m) (width), divided by 12, times 4 inches (10.2 cm) (thickness), divided by 27 = 2.96 cubic yards. Concrete is cheap and nothing is worse than coming up short (except rain). A good rule of thumb is to order an extra 5 percent rounded up to the next 1⁄4 yard (0.2 m). to handle spillage and uneven bases.[1]
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2Order from the nearest supplier. Get fresh concrete mixed near the site, not mixed across town by some company with a lower price.[2]
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3Ask for 5 percent “air entrainment” in the mix. Suppliers add a chemical that traps microscopic air bubbles to help the concrete handle the expansion and shrinkage caused by climatic changes such as freezing.[3]
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4Get the right strength. Tell them you're pouring an exterior sidewalk and they'll recommend the correct “bag mix” (ratio of cement to gravel and sand). In cold climates, they'll probably suggest at least a 3,000-lb. mix. That means concrete that'll handle a 3,000-lb. load per square inch without failing.
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5Have your checkbook ready. You'll have to pay on delivery after the concrete's unloaded.
Community Q&A
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QuestionHow much concrete is needed for a driveway that is 16 x 16 feet by 4 inches deep?
Community Answer16'x16'x4"=3.16 cubic yards. Typically it will take more than you think, I would plan for 3.5 - 4 yard depending on your grading. Also many concrete companies will give you a surcharge if you order less than 4 yards. -
QuestionHow much concrete do I need for a12x12x4 inches driveway?
Community AnswerMultiply those dimensions together and convert it to meters squared which directly converts to liters. -
QuestionHow much concrete is needed for a driveway that is 46 by 52 feet?Community AnswerThis depends on how thick you want your driveway to be. The minimum thickness should be four inches. Multiply 46' (552") by 52' (624") by 4" and you get 29.5 cubic yards.
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QuestionWhat is the least amount of concrete that companies will deliver?Community AnswerI have ordered one yard in the past, but this does not mean that it was any bargain, and it had crappy slump because it was the end of someone else's load. I sent it back for a fresh mix...
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QuestionHow much should be needed for 2000 square feet and a 4-inch depth?
Community Answer667 cf = 2000*4/12. Add a little for losses. -
QuestionWhat's the general cost for ready mix?Community AnswerIn my area, $95/yard, 4 yards minimum. Prices vary by location, and minimum required yards vary by company.
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QuestionHow many cubic yards per truck?
Community Answer10 yards per truck is the usual load, however, due to weight restrictions, some companies only carry 8 yards per load. -
QuestionHow much concrete do I need for a walkway that is 31' ×2' 1/2" ×4"?Community AnswerA quick way to do the math is multiply length in feet by width in feet and the depth is a fraction of a foot. For example 31 X 2.5 X (12/4) = 232.5 cubic feet. To go from cubic fee to cubic yards, divide the cubic feet by 27 as there are 3 feet in a yard and each dimension is a yard. 3X3X3 = 27. For your project you'll need 8.61 cubic yards. If the average truck is about 9 yards full, then get a full truck.
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QuestionHow do I know how much ready mix concrete I need when filling a hole?Community AnswerIs the hole rectangular like a trench or circular like a cylinder? For a trench, Length in feet x width in feet x depth in feet = cubic feet required cubic feet required / 27 = cubic yards required. Add 0.5 cubic yards or 5% to your order, whatever is larger to lower the risk of running short. For example, 100' long x 4' wide x 2' deep = 50 x 3 x 2 / 27 = 29.6 cubic yards, 29.6 + 0.5 = 30.1 | 29.6 * 105% = 31.08. In this case, an extra 0.5 yards is not enough to reduce the risk of running short. I would order 31 yards instead. For a circular hole: pi ~3.14. V = pi()*r*r*h, 1.5' wide by 4' deep. 5 different holes. 1.5/2 x 1.5/2 *3.14 x 4 = 7.1 | 7.1 x 5 = 35.3 | 35.3 / 27 = 1.3. Order 1.75 yards.
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QuestionHow do I measure for ready mix concrete?Community AnswerIn the United States concrete is delivered by the cubic yard. There are 27 cubic feet in a cubic yard. Multiply the length of your feature in feet, by the width in feet, by the height in inches divided by 12. For example, a 40 foot long, 4 foot wide, 5 inch thick slab: 40 X 4 X 5 inches / 12 inches per foot = 66.67 cubic feet, 66.67 cubic feet / 27 cubic feet per yard = 2.46 cubic yards. Order 2.75 or 3 yards as a cushion to lower your chances of running short. (A mis-measured average depth of 5.5 inches would instead take (40 x 4 x 5.5 / 12) / 27 = 2.72 cubic yards, so a small error in measurement or an uneven ground can really screw up your estimate and increase the chances of running short.
