Tools and Materials:
- Wooden stakes
- Mason's string
- 1" X 4" lumber for the concrete form
- 2" X 4" stud for the screed
- Steel wire mesh
- Side cutting pliers
- Steel tie wire
- 4' Level or laser
- Darby or bull float
- Magnesium float
- Steel trowel
Lay Out Your Slab's Location
The first thing to do is to decide on where the concrete slab will be located and what its size will be. Once you've got that nailed down, you'll need to drive stakes at the slab's corners, and connect the corners using string line. This represent 's your slab's boundary.
Be sure that your lines are square. Use the 3-4-5 method, then make any adjustments until you're spot on.
Prepare the Slab's Location
Pinch up the sod inside the area located within the string line. Next, level the dirt.
Now it's time to trench the footing. This is completely around the perimeter just inside the string line. Dig it one foot wide, and at least six inches deep. The purpose of the slab's footing is to strengthen and stabilize the slab.
Some municipalities require that a vapor barrier be placed on the dirt prior to pouring the slab. Inquire with the regional building code to determine whether this needs to be done.
The rationale for a vapor barrier is that moisture migrates up through the slab by capillary action and diffusion. This moisture is bad news for floor coverings and some folks claim it can be a health issue if mold develops.
Now, install steel mesh in the footing for small slabs, and rebar for larger slabs. Secure it together with pliers at the intersections with tie wire. This will strengthen the footing where the pressure is greatest. Again, consult your local building code for your particular situation.
Build Your Form
The concrete slab needs a wooden form to keep the concrete contained during its curing and finishing process. Use 1" X 4" or 1" X 6" boards for the form's sides. The string line serves as a guide and ensures your form is square and true.
You'll nail the form together. This is for stability; wet concrete exerts a lot of pressure! Drive stakes in every sixteen inches on the outside of the form, snug up against its sides. This will keep the sides of the slab straight.
It's critical to keep your slab level in all directions. Adjust the sides of the form to get this right. You can use a level for this but I really recommend a laser level. Then nail the stakes to the sides of the form securely.