Slab foundations are typically laid to serve as the base for garages, pole barns, sheds, and mobile homes. They are also used for the construction of new houses in place of a basement, cellar, or crawl space.
You can successfully build a slab foundation yourself that will last for many years to come. All you need is time, patience, materials, and some basic tools.
The first step in this project is to decide how big the foundation must be. If you're building it to be the base of a garage, pole barn, or shed, for example, then it will need to be the length and width of the building.
The thickness of the slab, the depth of the footers, and some other details will be dictated by your local codes and permits department. You'll need to check with them first to find out if you need to obtain permits anyhow.
The second step is to prepare the site. You’ll need to clear it of sticks, branches, rocks, and other debris. Then, you’ll need to level the area. You can do this by hand with a shovel and a pick if the ground is fairly level. It would be easier to use a backhoe, though, because you'll also need to dig footers around the perimeter of your slab foundation.
The third step is to use a measuring tape to measure out the length and width of the slab foundation. Use a long coil of durable string and some wooden stakes to mark the area out. Check the squareness of your marked out area by measuring from corner to opposite corner. That is, measure from the front, left stake to the rear, right stake. Then, use the measuring tape to check the measurement from the front, right stake to the rear, left stake. If your area is staked out correctly, these two measurements should be the same. If they aren't, then recheck to make sure the lengths and widths are correct.
The fourth step is to dig out the footers. Again, if the slab foundation is fairly small, you can do this by hand with a shovel and a pick. But, it would be much easier to use a backhoe.
Footers are narrow ditches that are dug out along the front, back, and both sides. They are positioned so that they end up being underneath the outer sides of the foundation. The purpose of the footers is to support the weight of the concrete slab plus the added weight of the building.
After you have dug out the footers it's time to pour concrete into them. Either follow the manufacturer's directions on the concrete bags, or, hire a local company to bring in premixed material.
Once the footers have properly set, it's time to lay the actual slab foundation. To do this, you'll need to use two by fours or two by six pieces of wood. Each board should be as long as the width and length of the area. These boards will serve as the form for the additional concrete. Don't try to nail two boards together to reach across an entire side because the two pieces will be weak in the middle.
Lay the two by fours or two by sixes out so that they form the base of the slab. Nail them together securely at their corners by using ten penny nails.
Finally, fill the forms all the way full with premixed concrete. If the concrete is going to be laid very thick, then you'll need to lay rebar across it. The rebar helps to reinforce the concrete so it doesn't break or crack as easy.
Use a trowel or a long two by four to level the concrete out. Once it is cured, you can begin your building.
