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.

Tools

You may choose to rent a concrete mixer and a plate compactor.

Project details

Skill

Cost

Estimated Time

Tools & Materials

  • Wheelbarrow
  • Pointed shovel
  • Bucket - 5-gallon
  • Cordless drill/driver
  • Concrete float
  • Push broom
  • Concrete edger
  • Concrete groover