Pouring a Concrete Slab
The first thing the homeowner should consider when planning a patio, carport, outside storage shed, or a freestanding patio cover is the concrete slab. Pouring a concrete slab need not be difficult with the right planning. Since this is a DIY project, the concrete slab cost is reasonable.
If the slab is to be a foundation for framing a house, it must be smooth and level.
This article in the DIY concrete slab series provides instructions for pouring a concrete slab. The second will explain troweling and finishing the concrete slab. The third explains concrete formulations.
If there is any plumbing involved with the slab, consider it in the concrete slab design. The same goes for any electrical conduit supplied to the slab.
Failure to prepare for these concerns means the concrete slab will need to be trenched and patched, a tedious process not to be reckoned with!
Tools and Material List
- Hammer
- Wooden stakes
- Mason's string
- 1” X 4” lumber for the concrete form
- 2” X 4” stud for the screed
- Shovel
- Steel Wire Mesh
- Side cutting pliers
- Tie wire
- 4' Level or laser
The initial thing is concrete slab design - location and its size. Drive stakes at the corners and connect the stakes with string. This is the the slab's boundary. Ensure that it's square with the 3-4-5 method. Make any adjustments needed.
Prepare the Slab's Location
Dig up the grass inside the area defined by the string line. Level the dirt. Trench the footing around the perimeter. It should be a shovel width wide and six inches in depth. The purpose of the slab's footing is to lend strength and stability to the slab.
Some locales require that a vapor barrier be placed under on the dirt prior to pouring the slab. Inquire with the regional building code to determine whether this needs to be done.
Steel mesh is now laid in the footing. Wire it together with the pliers at the intersections using tie wire. Using the mesh is analogous to using rebar in road construction. It strengthens the footing where the pressure is greatest.
Building the Form
The concrete slab needs a form to keep the concrete in place during the drying and finishing process. The 1” X 4” boards form the form's sides. The string line ensures the form is square.
Nail the form together for stability purposes. Drive the stakes in every sixteen inches outside the form and contacting the 1” X 4” boards. This contains the pressure of the wet concrete and keeps the sides of the slab straight and true.
It's important to keep the slab level in all directions. Adjust the sides of the form to get this right. Nail the stakes to the sides of the form securely.
Pouring the Concrete into the Form
Home improvement outlets and tool rental facilities rent out portable cement mixers. This is the way to go for any patio, shed, or carport slab project. Position the cement mixer's chute to pour the concrete into one end of the form. Begin the pouring and use the shovel to push the concrete and work it into all areas.
After filling the form, level it with the edge of the 2” X 4”. Push and pull it in a sawing motion across the form's top starting at one end and working down to the other end. This process is called the “screed”.
The next article in the do it yourself concrete slab series will cover finishing the slab. It will revisit the screed and go on to explain the darby, edging and grooving, and floating and troweling the concrete slab.
After finishing the slab, stay off of it for a couple of days with anything heavy, and at least five days for a driveway.
 |
 |
 |
