How to Pour Concrete Slabs for Metal Buildings

Choose a concrete product that pleases you and purchase enough to make as many standard 6 feet by 6 feet by 4 inch thick slabs and you require. Consult the packaging of the concrete that you choose to find out how much pour area one purchase will fill, since this will vary by product brand and size. Use this information to calculate your purchase. Have the concrete prepared at the store and placed in air-tight containers.

Clear the locations for your slabs of any structures, debris, and plants. Remove the grass so that each of the areas is just bare land.

Use 2x4 lumber to create frames in which to pour your slabs. Nail one of the 6-foot boards to one of the 8-foot boards, 1 foot in from one end. Nail the other 6-foot board 1 foot in from the other end. Attach the remaining 8-foot board so that it is even with the first 8-foot board and each of the 6-foot boards are 1 foot in from each end of it. Use a tape measure to check that your frame is a perfect 6 foot x 6 foot square. Position the frame properly. Make as many more frames as required for your number of slabs and lay them into place.

Place 3 2-by-2-inch wooden pins along each side of the pour frames, snug up against the frames themselves. Push them into the ground using your hand, then hammer them until they are halfway underground. Cut off the tops of all of the pins with a handsaw so that the tops of the pins and the tops of the frames are all level.

Use a shovel to create a trench around the interior perimeter of each frame. Make each trench approximately 4 inches deep and no wider that the spade of your shovel. These spaces will make the concrete thicker around the edges, meaning that your slabs will be stronger.

Use a garden hose to carefully moisten the center dirt within each frame and tamp the ground inside of each with a long-handled tamp until all of the surfaces are level and tight.

Before pouring the concrete, cover all of your bare skin and put on some gloves and a pair of plastic goggles.

Empty enough of the concrete for one slab from the airtight containers into a wheelbarrow or other easily transportable vehicle. You will now need to work quickly.

Pour a thin, about 1-inch thick, layer of concrete into the first frame and use a shovel to spread it around. Position the 5-foot-long reinforcing rod over the estimated center of the concrete and drop it atop this first layer. Wrap a piece of #3 rebar around the inside of the pour frame, keeping a 2-inch space between the rebar and the sides of the frame. Carefully bend the rebar around each corner, rather than cutting it, which creates weak spots. Where the rebar overlaps the reinforcing rod, tie them together with tie wire so that they do not rub back and forth. If the rebar overlaps itself at the ends, also secure these together with the tie wires.

Pour the rest of the concrete into the frame. With a hammer, bang on each side of the frame so that the air bubbles burst and the concrete settles.

Screed the surface of the concrete, working the tool from one end of the frame to the other in a back-and-forth motion. Smooth the concrete with a rubber float using big, circular motions. Allow the concrete to cure for 30 minutes, then float the concrete again. After another 30 minutes, use the float to smooth the surface a final time, then let the concrete dry until all of the water evaporates from the surface. When it is soft-set, use a metal trowel to shape the surface of the concrete until you are happy with how it looks.

Fill the rest of your pour frames with cement following Steps 8 through 11.

Cure all of the concrete slabs for 3 days, spraying them lightly with a garden hose once a day to keep the cure even. Once all of the slabs have completely cured, remove the pour frames.