Garage addition project: part 4, the concrete slab
There is a good chance that installing a concrete slab is going to be one of the early construction phases of your home addition. About the only type of residential construction that doesn't involve a concrete slab is a crawl space without a garage. Prepping and pouring a concrete slab involves a lot of labor, and there are important details which shouldn't be missed in the rush to pour the slab while the weather is cooperating.
Ask your contractor to use a concrete pump
Concrete trucks are big and heavy, and can do a lot damage getting in and out of a job site with an established lawn. Ask your contractor to use a concrete pump for the footers, foundation, and slab. It is going to cost a little more, but can save a lot of damage to your property. As you can see in the video, the trucks stay in the street and the pump puts the concrete in place.
Concrete slab details
The concrete slab in your home addition usually consists of 4 inches of concrete over 4 inches of gravel or stone. If you have any plans for plumbing, plumbing ground-works may need to be installed prior to the gravel being graded.
Once the stone has been leveled, a few other details need to be taken care of prior to the slab being poured.
- Perimeter insulation. Styrofoam insulation should be installed around the perimeter of the slab area.
- Vapor barrier. A vapor barrier should cover the entire area to be poured.
- Wire mesh. Wire mesh is installed over the vapor barrier to tie the concrete together.
- Grade stakes. Your contractor installs grade stakes to help keep the concrete at 4 inches deep.
- Under slab drainage. Any drain tile for under slab drainage needs to be installed.
Make sure your contractor picks a day to pour that isn't excessively hot or cold and that rain isn't in the forecast, as these conditions can be damaging to your concrete slab.