How to Fix a Hole in a Slab Vent

Vents in concrete slabs are used to allow air or moisture to pass through the slab. The air transfer from the vent is important for climate control inside basements. A hole is made in the concrete to fit the slab vent in, so holes near the vent can potentially do more damage because a small crack near the vent can quickly turn into a larger hole.

Wire brush
Shop vacuum
Concrete floor patch material
Trowel

Instructions

- 1
  Remove any large pieces of broken concrete from the hole.
- 2
  Wash the hole with water and then scrub the hole with a wire brush. You do not need to rub the hole until it is completely smooth. You want the edges to be a little rough to help the patch bond to it.
- 3
  Suck up the water and any remaining debris with a shop vacuum.
- 4
  Mix in the directed amount of water to the concrete floor patch. Some concrete floor patches do not require water to be added at all. However, most floor patches are made of cement and require water to be added before use.
- 5
  Apply the floor patch to the hole. Avoid getting any of the material inside the vent. You want to completely fill the hole in. It is better to use too much material than too little.
- 6
  Smooth the floor patch down using a trowel. Scrape up any extra material using the side of the trowel. The top of the patch should be even with the rest of the concrete slab. It takes about 24 hours for most floor patches to dry completely.

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