What Is Bag Mix for Patio Prepared Concrete?

Basics

• Though cement and concrete are often used interchangeably, they are two different materials. Cement is a dry powder made primarily of lime and silica. Concrete is a hard and durable substance that requires cement, gravel or crushed stone aggregate, sand and water. Mixing your own concrete can save money, though determining the right proportions of substances can be tricky for beginners. Buying premixed bag concrete can cost a bit more but instructions only require adding water in the prescribed amounts. The chances of incorrect proportions or other mistakes are reduced, making it a better alternative in building patios for the less-skilled handyman.

Types

• Prepared concrete mixes come in several types for applications. For patio slabs, regular mix is more commonly used. Fiber reinforced concrete contains more cement and hundreds of tiny fibers. It eliminates the need for wire mesh because it is designed to reduce chipping, flaking and cracking. Lightweight concrete is made with lightweight coarse aggregate. It covers more cubic feet than the same amount of regular concrete and is lighter. For topping or patching chipped concrete patios, sand mix puts together Portland cement and graded sand, but is useful only in 2-inch thickness or less. Gravel-mix fiber-reinforced mix does the same thing as sand mix but for a thickness of more than 2 inches.

Measurements

• The number of bags of concrete required for a patio depends on the square footage, the thickness of the slab and the size of the bag. For a 4-inch-thick slab, 15 square feet requires 10 60-pound bags and 7 1/2 80-pound bags. At 20 square feet, the number changes to 13.3 60-pound bags and 10 80-pound bags, and at 35 square feet, the material requirements are 23.3 and 17.5 bags respectively. For a 6-inch thick slab, 15 square feet needs 15 60-pound bags and 11.25 80-pound bags. A patio measuring 20 square feet needs 20 60-pound bags and 15 80-pound ones, and 35 square feet needs 35 60-pound bags, and 26.25 80-pound ones.

Tips

• Bag mixes for prepared concretes require some precautions for safe use. Concrete contains some corrosive properties than can irritate the skin, eyes or lungs with direct contact. Use a mask and work in well-ventilated areas to avoid breathing in the substance. Wear waterproof gloves and boots to protect the hands and feet. Use kneepads to protect your knees when placing the slab, and use your legs rather than back when lifting the heavy mix bags.