Concrete sidewalks are installed as slabs that are defined by lines, also known as control joints. The lines run across the walkway at intervals and limit cracking of the concrete with ground movement. Typically, the homeowner or property owner is responsible for maintaining the sidewalk in front of the property, which includes replacing broken slabs. In many localities, a permit and inspections are required when performing work on sidewalks. This ensures the concrete mix and finishing are correct. Obtain the permit before starting work and call for inspection after the forms are installed.
Set up a safety barrier around the work area with delineation cones and yellow caution tape. Allow plenty of room inside the barrier to perform the work.
Put on safety gear to protect your eyes and ears. Separate the section of broken slab by cutting each of the control-joint lines at the adjacent sections of the sidewalk with a jackhammer that's fitted with a 3-inch-wide cutting bit. Cut the main portion of the broken section into manageable size pieces. Remove the broken concrete.
Remove any concrete debris from the section. Grade the dirt where the concrete was removed to a uniform surface with a steel rake.
Cut pieces of pressure-treated two-by-fours as a form for each side of the sidewalk section where the concrete was removed. Each end of a form extends past the corresponding end of the adjacent sidewalk sections 24 inches. Cut the two-by-fours with a circular saw.
Install the forms flat against the outer edges of the existing sidewalk with the upper edges even with the surface of the existing sidewalk.
Drive 12-inch wooden stakes against the outer sides of the forms every 12 inches from end to end with a steel mallet. The tops of the stakes are even with the upper edges of the forms. Secure each stake at the sides of the forms with two 6d duplex nails and a hammer.
Call for an inspection of the forms and the dirt substrate where the broken slab was removed.
Pouring and Finishing
Stage a mixing tub near the area of the forms. Add 1 gallon of fresh water with a garden hose. Add the correct proportion of concrete mix and an admixture that's specified on the permit. Turn the mixture in the tub repeatedly with the shovel and add water, as necessary, so the mixture is medium consistency instead of too dry or wet.
Shovel the wet concrete into the formed section, and fill the section to the tops of the forms. Use a 4-foot-long piece of pressure-treated two-by-four as a screed board to level the wet concrete. Hold the board on edge atop the forms at one end of the section and slowly drag it across the surface of the concrete toward the opposite end of the section. Remove any excess concrete with the shovel.
Smooth the surface of the fresh concrete with a wood float. Allow the concrete to set for 20 minutes and round the outer edges of the section at the forms with a concrete edging tool. Insert the curved edge of the tool into the seam between the concrete and a form and use long, even strokes with the tool for the best results.
Smooth the surface of the fresh concrete to a uniform finish with a steel trowel. Create control-joint lines where the fresh concrete meets the existing sections with a liner tool. Use medium pressure with the tool to avoid gouging the surface of the new sidewalk.
Allow the concrete to cure overnight before removing the stakes and forms.
Things You Will Need
- Delineation cones
- Yellow caution tape
- Safety glasses
- Ear protection
- 3-inch-wide cutting bit
- Steel rake
- Pressure-treated two-by-fours
- Circular saw
- 12-inch wood stakes
- Steel mallet
- 6d duplex nails
- Mixing tub
- Garden hose
- Concrete mix
- Wood float
- Edging tool
- Steel trowel
- Liner tool
- For larger sections, order ready-mixed concrete from a concrete supplier. Depending on the amount of concrete needed, enlist a concrete pump service to pump the wet concrete, if necessary.
- Do not use wire mesh or steel reinforcement bars in the concrete sidewalk unless specified by the public works department or the building department that issues the permit.
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