July 16, 2015
An 80 lb bag of QUIKRETE® Concrete Mix yields 0.6 cubic feet of concrete when placed. A patio that is 170 square feet and 0.33 feet (4 inch) thick will require 56-57 cubic feet of concrete, or 95 80 lb bags. Yields will vary based upon waste, uneven subgrade, etc. It is crucial that you have sufficient equipment and man power to allow you to pour the entire slab, or sections that are separated by expansion joints, before any of the material in that section has set. If some of the material sets before subsequent bags are poured, a cold joint will form. A cold joint is caused by the inability of the product to intermix between bags, and prevents the slab from being a single, solid mass. A cold joint may cause problems ranging from a simple aesthetic issue, to as serious as potentially allowing for water intrusion into the cold joint, which may eventually lead to concrete degradation. Please contact the QUIKRETE® Technical Center directly at 1-800-282-5828 if you have any further questions.
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