Does an Air Conditioner Need Rebar Footing?

Rebar Footing

• Concrete is an extremely versatile and strong construction material, but it can have relatively low tensile strength. This means concrete is good at resisting being crushed but is prone to cracking. For this reason, rebar, or steel rods, are often added to the concrete as it is poured to give it more tensile strength.

Condenser/Compressor Pads

• The role of a condenser/compressor pad is mostly just to keep the air conditioner up off the wet soil. The unit is designed to be exposed to the elements, but it needs to have a solid foundation and must be prevented from moving or sinking into the soil. The air conditioner components are not so heavy so as to necessitate a rebar footing, and an ordinary poured-cement pad should be more than sufficient.

Pouring the Pad: Build the Mold

• Measure the air conditioner compressor and establish how large the pad will have to be. Dig out at least 2 inches of soil in the area where you will pour the pad. Construct a wooden form in the size and shape you intend to make your concrete pad. Use 2-inch-by-6-inch pieces of lumber to make the form and secure the four pieces together using 4-inch screws. You do not need to construct a wooden floor for your mold; a 1-inch layer of pea gravel will be sufficient. Place the form where you intend to pour your pad.

Pouring the Pad: Pour the Concrete

• Mix your concrete in batches in a 5-gallon bucket. Mix the dry concrete mix with the amount of water indicated by the instructions on the bag, using a drill with a cement mixing attachment to speed up the process. Once the concrete is mixed, pour it in the mold and mix a new batch, repeating the process until you have at least 4 inches of concrete poured. Use a concrete trowel to level the concrete before it cures. Allow sufficient time for drying, as indicated by the instructions on the bag, before removing the mold. A 4-foot-by-4-foot-by-4-inch pad should take approximate 10 bags, 80 pounds each, of cement mix.