3 out of 5ModerateMixing, pouring, and finishing concrete is challenging.
$500 to $700 per 100 square feet at 4 inches thick
2 to 4 hours for a small- to medium-size slab
Working with concrete
- Portland cement is the key ingredient in most masonry mixes, including cement, concrete, and mortar.
- Concrete is composed of portland cement, sand, and aggregate (gravel). When the concrete cures, the aggregate binds the ingredients and makes concrete strong.
- Mortar, used to build brick and concrete-block walls, is made of portland cement, lime, and sand; it contains no gravel.
- Lime makes mortar sticky so it adheres better to the brick or block, and it also makes cured mortar more elastic and less likely to crack.
- Portland cement mix is used for below-grade brick and block walls. It’s a simple mortar mix of only portland cement and sand.
- To make your own concrete mix, use three parts sand, two parts gravel, and one part portland cement.
- To mix concrete, you can rent an electric or gas-powered cement mixer, or mix it by hand in a wheelbarrow.
- Use a bucket to ensure accurate measurements. We recommend a 1- or 2 gallon bucket for mixing the dry ingredients. Add one part sand, one part portland cement, and one part gravel to the wheelbarrow. Blend well with a pointed shovel.
- Add remaining dry ingredients—two parts sand and one part gravel—and mix well until thoroughly blended.
- Smooth out the dry concrete mix in the wheelbarrow and excavate a small hole in the center.
- Partially fill a 5-gallon bucket with water, then pour about a quart or so into the center of the dry concrete mix.
- Mix well with the shovel, add a little bit more water, and mix again. Repeat until the concrete is the consistency of cookie dough. If too dry, add a bit more water. If too wet, add a little more dry mix of cement, sand, and gravel in the proper proportions.
- Excavate the area where you’re planning to pour the concrete. Dig down to solid, undisturbed earth.
- Build a wooden form out of 2x boards to hold the concrete in place until it cures. Fasten the boards together with 3-inch deck screws.
- Add several inches of ¾-inch stone to the form and compact it well with a plate compactor or hand tamper.
- Carefully dump or shovel the concrete from the wheelbarrow into the form, filling it about halfway.
- Smooth out the concrete, then lay down some ½-inch (No. 4) metal reinforcing bar or welded wire mesh to add structural strength to the concrete.
- Mix more concrete, if necessary, and fill the form to the top.
- Smooth out the surface of the concrete with a steel float.
- Allow the concrete slab to dry for about an hour, then lightly drag a push broom across its surface to add texture.
- Run an edger around the perimeter of the slab to round over its edges.
- On larger slabs and walkways, used a groover to cut control joints into the still-soft concrete.
- Allow the concrete to cure, then carefully unscrew and remove the form boards.
- Backfill as necessary around the slab with soil.