How to Install a Concrete Slab

The most important aspect of installing a concrete slab patio on your home is to make certain that the ground underneath the patio is flat and level before you pour the concrete. If you avoid this step, it will lead to cracks in the concrete and may make it necessary to remove the existing pad and replace it with a freshly poured patio, effectively doubling your expenses for the project, in addition to adding the disposal fee for getting rid of the broken concrete.

Building a concrete slab isn't all that difficult, though, to be honest. You'll need to invest in some tools before you start, including a concrete float, a trowel, wheelbarrow and a garden hoe, as well as a curbing trowel and a tool that allows you to form the stress relief joints in the cement.

Begin by excavating the area where the concrete slab patio will be installed. You'll need to dig down at least 12 inches for smaller patios, such as those that measure no more than five by ten feet, but for patios that are any larger, a depth of 18 inches is a good idea. This allows you to add additional paver base sand to the excavation and prevent problems with the concrete cracking.

Fill the base of the excavation with no less than six inches of paver base gravel. If you have an 18 inch deep excavation, use ten inches of paver base gravel. At this point, you'll need a soil compactor. These tools are widely available for rental. The machine works by jumping up and down on the paver base, packing and leveling the material until it is tightly pressed into place.

Fill the excavation with 4 inches of paver base sand. The paver base sand then needs to be packed into place with the soil compactor, as well.

When the paver base is in position, you can now place the four form boards you'll need to make certain that the edges of the concrete slab are straight and true. To install these, simply set a two-by-two post into each corner of the concrete slab excavation, and then attach the form boards to the posts. Keep in mind, however, that the form boards should be positioned so that the corners of the patio are straight, not notched.

Mix the concrete with water until it is of a slightly thinner consistency than peanut butter. This will give you additional time to float and form the concrete before it begins to set. Use a wheelbarrow to mix the concrete, and then pour the concrete into the excavation.

Work the concrete around the form with the concrete float until the surface begins to appear flat. When the surface is adequately flattened, you will then be able to add the stress relief channels into the patio surface. These channels should be positioned every eight feet. This means that they are not necessary on smaller patios, but are necessary on larger patios. They provide a place for the concrete to crack where it isn't obtrusive. After the stress relief channels are in place, use the curbing trowel to round off the sides of the patio, and then allow it to cure for at least a week before walking on it. After the concrete has fully cured, you can remove the form boards and backfill the dirt around the sides of the patio slab.