How to Lift a Sinking Concrete Slab

An uplifting way to rescue a sunken walkway with This Old House landscape contractor Roger Cook

In this video, This Old House landscape contractor Roger Cook shows how to lift a sinking concrete slab.

1. Cut through slab with gas-powered saw fitted with 12-inch diamond blade; that'll allow the sunken slab to lift up.
2. Use diamond-tipped core drill to bore several large-diameter holes through slab.
3. Use a pneumatic rock hammer to drill a 12-inch-deep hole through each core hole.
4. In a mobile mixer, blend a grout mixture of sand, silt and Portland cement; mix the grout with water in auger.
5. Use a hydraulic concrete pump to pump the grout through the core-drill holes.
6. Continue to pump grout into the holes a little at a time until slab starts to rise up.
7. Once the slab is level, cement the concrete-core plugs back into holes.
8. Push the plugs flush with the slab, then use sponge to clean the area around the plugs.


TV Listings

Find TV Listing for This Old House and Ask This Old House in your area.