Intermediates: Laying the Foundation for Covered Spaces

Laying the foundation for covered spaces, like garages, requires prep work. With a solid plan in place, the work can be completed within a weekend. Before starting your project, keep in mind that large-scale extensions and new covered spaces likely require approval from your local building department. Once you have those formalities settled, a correctly drained foundation can be installed.

For garages, mark out the area of the floor you’ll be working with using spray paint. Draw out the floor plan to scale on graph paper. The ground that the foundation will be laid over should be level and drained. This can be done by digging three inches into the soil and filling with pea gravel. Ensure the gravel is firmly patted down.

Footings need to be taken care of next – they are the trenches that run along the inside perimeter of the slab. Digging down at least eight inches is best. Each trench should be at least four inches wide. When the slab is poured, it will anchor the concrete pad in place.

Next, lay half-inch rebar in the trench on small rocks or chunks of cinder block so that they are held up at least two inches from the bottom of the footing trench. Build a 2 x 6 frame around the rim of the footing trench and hold the frame in place with stakes that are pounded into the ground.

When you are ready to pour the slab, lay down 4 x 4 crib wire and more rebar. It’s best to keep the rebar and wire tied together to keep the slab from cracking as the ground moves over the years. Pour the footings first and agitate the concrete as it is being poured or pumped with an electric vibrator or a wooden tamp. This will get all of the air bubbles out of the mix.

When the footings have been poured and secured, pour the main slab. While it’s easiest to have it pumped in, this can also be done manually but you’ll likely need the help of some friends who can maneuver the cement flat with shovels.

Once the concrete is poured, it will need to be leveled. A 2 x 4 lumber can be used to tamp down the mixture by moving it back and forth quickly. Low spots will need to be filled with cement and then leveled down again. This needs to be done as quickly as possible because the concrete may start to stiffen within 30 minutes depending on the temperature.

Once the concrete slab has leveled out, the finishing process entails using a steel pole trowel to float the surface of the slab. Keep at it until you’re sure there are no bumps. Once the slab is shiny and smooth, let it set until it begins to dry out.