How to Pour a Concrete Slab for a Garage
- 1). Stake out the area where your garage will be, and string twine between the stakes.
- 2). Scrape the entire area using the tractor to clear it and dig about 6 inches into the ground.
- 3). Use the backhoe to dig a trench around the outer perimeter of the excavated area. The depth will vary according to local codes, but generally for a single-story garage, you’ll need 8 inches of depth, and for a two-story garage you’ll need 10 inches. In some areas prone to cold winters, the depth could be as much as 48 inches, so you need to check local building codes. The footing you’ll pour in that trench will be 2 feet wide, and you’ll need room to work in there, so dig the trench about 6 feet wide.
- 4). Use the 2-by-10 lumber and stakes to build forms for the concrete footings in the trench. If you have determined a different depth in the previous step than 10 inches, use lumber appropriately sized for the depth you want.
- 5). Run the half-inch rebar along the length of the forms on the inside. The concrete will dry around the rebar and be reinforced by its steel. Keep it above the ground using rocks or scraps of wood.
- 6). Pour sand into the trench to a depth of about an inch.
- 7). Have the concrete truck pour wet concrete into the form walls. Spread it and smooth it by running the 2-by-4 along the top surface of the forms.
- 8). Place your mechanical vibrator against the forms to vibrate the concrete and liberate any air bubbles that may be trapped in the wet mixture.
- 9). Allow the footings to dry for at least two days before removing the form lumber.
- 10
Tamp the excavated ground inside the footings, then lay a 2-inch layer of sand and tamp that down as well. - 11
Lay rebar in a grid, 16 inches apart on top of the sand to reinforce the slab you’re about to pour. - 12
Have the concrete truck pour more concrete into the center of the footings. You’ll be using the footings as the form for the slab in the center. Again, use the 2-by-4 to smooth the surface of the wet concrete by running it along the top of the footings. - 13
Allow the slab to dry for at least two days before walking on it, and allow a month for it to cure fully.
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