A small concrete slab, 5-foot by 5-foot square, used for air conditioner placement, a small hot tub or as a concrete landing at the bottom of a set of stairs, is quick to pour and requires a minimal amount of physical labor. Due to the small size, one or two people can form and pour the pad if they have the correct tools and a little knowledge of concrete pouring procedure.
Things You'll Need
- Dimensional lumber
- Circular saw
- Measuring tape
- Hammer and nails
- Carpenter’s level
- Rebar chairs
- Concrete tools
Prepare the site. A common mistake made by homeowners when they form and pour small pads, is to pour over unprepared ground. Remove all weeds, grass or turf before pouring. Anything underneath the concrete that can biodegrade will do so, creating voids and causing the pad to crack.
Determine the desired height of your pad and dig to a depth of 5-inches below that point. For instance, if you want the pad to be 2-inches above grade, dig to a depth of 3-inches below the surface. Dig the hole at least 6-feet by 6-feet square to allow enough space to maneuver your forms.
Cut four 2-inch by 4-inch boards to a length of 63-inches long. Nail the boards to each other, overlapping the extra two inches at each end. Use only one nail per end until the form is square.
Square the form by using the “3, 4, 5” method of creating an exact 90-degree angle. Measure 3-feet upwards from one inside corner and mark the spot with a pencil. Measure 4-feet along the adjacent board and make one more mark. Take your measuring tape and hold it between the marks. It should measure exactly 5-feet when the corner angle is correct.
Put stakes on the outside of the form as you square it to hold it in place. Once all the stakes are set, reinforce the form by nailing the ends with another nail. Nail the stakes to the form after you’ve determined the correct grade.
Level the top of your 5-foot by 5-foot slab, making sure you allow a slope for drainage. The standard slope for drainage uses a drop of ¾-inch for every 4-feet. Fill the bottom of the pour with 1-inch of sand and reinforce the pour with rebar, set on rebar chairs.
Order the concrete. To pour a 5-foot by 5-foot slab, 4-inches thick, you'll need to order 1/2-cubic yard of concrete. If you desire a different thickness or more than one pad, use a handly online calculator to determine your needs. Order slightly more than you need for insurance purposes. (See Resources)
Use shovels to spread the wet concrete into the corners, pushing and prodding to work it downwards. Use the sharp edge of the shovel to slice into the wet concrete, removing voids and air bubbles. Work very quickly, once the wet concrete is in the form, you have a limited amount of time to smooth it.
Use a bull float on the surface, sliding it back and forth to smooth out the wet concrete and bring the finer particles to the surface. Once the top is smooth, stop floating it and use an edge trowel around the perimeter to form a rounded corner.
Spray the concrete pad lightly with a garden hose, just barely misting it every hour or so for the next few hours to allow it to cure slowly and strengthen the integrity of the concrete.