How to Cut a Trench in Sidewalk Drainage

Good drainage is essential for a sidewalk. Without it, the foundation could wear away over time, causing the slab to sink. On the surface, standing water can create unsightly pits and cracks. Cutting a trench to run parallel with a sidewalk is an effective way to capture water runoff and carry it away quickly. Installing a pre-cast trench is a straightforward process that beginner do-it-yourselfers could do over a weekend.

Shovel
Trenching hoe
Gravel
Pre-cast trench
Concrete
Wheelbarrow
Hoe
Paddle bit
Drill
Scooper
Cloth
Trowel
Drain grate
Screws

Instructions

- 1
  Dig out a 7-inch-wide trench along the low-lying side of the sidewalk with a shovel and trenching hoe. The trench should be 8 inches deep and release into a ditch, dry area or other designated outlet. Dump the soil on a tarp so you can reuse it over low areas in the yard.
- 2
  Cover the bottom with a 3-inch layer of gravel and spread it evenly with a hoe.
- 3
  Place a pre-cast trench on top of the gravel down the center of the trench, adjusting the amount of gravel so the lip of the trench sits slightly below ground level.
- 4
  Mix concrete in a wheelbarrow with concrete mix and the specified amount of water. Stir the concrete with a paddle bit and electric drill so it is thick but spreadable.
- 5
  Scoop the concrete into the gaps between the pre-cast trench and the soil using a scooper. Wipe off any concrete from the top of the lip with a cloth. Tamp the concrete down and smooth the top with a trowel so the concrete sits just below the lip.
- 6
  Attach the drain grate over the top of the trench to prevent people from tripping and improve the appearance. The grate will snap or screw into place, depending on the manufacturer. Plan to check the trench regularly to clear it of leaves and other debris so it doesn’t become clogged.

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