Pouring concrete as a stand-alone walk or as a base for other mortared materials.
You can pour concrete as a stand-alone walk or as a base for other mortared materials such as brick, tile, or stone. The only difference is that a walk that will be a foundation for other materials must be put deeper into the ground so the finished surface won't be too high.
For a plain slab walkway, consider using coloring, stamping, or texturing techniques.
Concrete walks often abut an existing concrete or masonry structure. Any time you pour concrete next to existing materials, you must install an expansion strip on the old structure. The strip cushions the expansion and contraction of the materials and prevents damage.
These procedures assume the proper layout and excavation of the site prior to working with the concrete.
About 20 hours to prepare, pour, and finish a 4x25-foot walk
Layout and excavation tools, wheelbarrow, tape measure, mason's line, cordless drill, circular saw, concrete mixer, mason's hoe, darby, edger, jointer, float, screed, broom
Laying out square lines; form building; mixing, pouring, and finishing concrete
Prepare and excavate the site
2-1/4-inch screws, 2x lumber for forms, expansion strip, gravel, wire mesh, dobies or wire balusters, soft-iron wire, form-release agent, concrete, construction adhesive, plastic sheeting or burlap
Lay out the site and remove the sod, excavating to the depth of materials required by local codes. Set up the intersection of your batterboard lines (and ground stakes) to correspond with the outside edges of the forms. Drive 2x4 stakes at 2-foot intervals, with their inside edges under the lines. Fasten the 2x forms to the stakes with 2-1/4-inch screws, checking the slope of the forms with a slope gauge and adjusting the slope by raising or lowering the forms as you fasten them. If any stakes are higher than the top of the forms, cut them off level with the 2xs. If you've designed the walk to slope to the side, use a slope gauge placed across the forms.
Shovel in about 2 inches of gravel and level it with a garden rake. Then compact this layer with a power tamper. Shovel in the remainder of the gravel (for a total of 4 to 6 inches), level it, and tamp it. Lay 10x10-foot wire reinforcing mesh on the gravel, leaving about 1 inch between the ends of the wire and the forms, and overlapping sections by at least 6 inches. About every 3 feet, set dobies or wire balusters (also called chairs) under the intersections of the mesh and wire the mesh to these supports. The object is to raise the wire mesh to the approximate center of the slab.
Mix the concrete and use a wheelbarrow to move it to the work site. Don't load the wheelbarrow to the top; a full load is more likely to tip sideways as you move it. Start pouring in the farthest corner of the walk and then back to the mixing site. Work the mix against the forms with a shovel and garden rake.
Before you level the concrete, consolidate it by working a 2x4 up and down in the mix. Work a shovel along the edges to release any air bubbles, and tap the corners and edges of the forms with a hammer to help release trapped air. Then cut a straight 2x4 about a foot or so longer than the width of the walk and pull it in a seesaw motion down the walk. Work out bumps in the concrete, fill in low spots, and screed again.
After you've finished floating the surface, run a pointing trowel along the inside edge of the forms to help break the bond between the wood and concrete (it'll be easier to remove the forms later). Then run an edger along the outside edges of the concrete to round them. Rounded edges will not chip as readily as square edges. Omit this step if you're going to mortar brick, tile, or stone to the slab.
Cut control joints in the slab with a jointer. To keep the joints straight, tack a 2x4 with 2-inch screws to the top of the forms -- exactly perpendicular to the forms (use a framing square to measure the angle). Space control joints at intervals equal to 1-1/2 times the width of the walk (every 6 feet for a 4-foot walk).