How to Underpin a Patio

Examine the patio to see where it needs repair. The lowest part of the patio will need the most support.

Start digging under the lowest corner of the patio with a shovel. Continue digging until you can fit a jack under the concrete slab.

Support the slab with the jack and slowly raise it back up to the original position.

Continue digging under the patio to make room for the new concrete. You'll need to dig until you reach a solid base of either rock or hard soil.

Wedge wood support beams or boards under the concrete to help support the load as you dig.

Mix the concrete in a wheelbarrow by adding water. Follow the package instruction. Use a non-shrinking concrete mix that is designed to adhere to existing concrete.

Shovel the concrete into the hole you have created so that it is packed full and even. Remove the jack once the back of the hole is filled. Continue adding concrete until the under hole is filled. Smooth the edge with a trowel.

Allow the concrete to cure for up to a week. Fill in the soil around the patio.