How to Repair a Block Concrete Structure

Concrete blocks create very strong structures but can develop problems if they are exposed to too much moisture, excessive heat and cold or movement from an earthquake, blasting or being hit by something like a truck. Repairing a concrete block structure can require a lot of hard work, but the theory behind it is straightforward. Provide adequate drainage so the structure is protected from water, and apply good mortar to all bonded surfaces to create a strong structure.

Small sledgehammer
Framing hammer
Cold chisel
Mortar
Trowel
Epoxy-based cement repair compound
Caulking gun

Instructions

- 1
  Remove any blocks that have been damaged. This includes blocks with surface cracks and blocks that have pieces missing. Break the block up with a small sledgehammer, taking small, controlled swings at the damaged block to avoid damaging the blocks around it. Remove all parts of the broken block. Clean out the mortar on the sides of the hole using a cold chisel and a framing hammer.
- 2
  Apply fresh mortar to the inside faces of the hole that you created by removing the broken block. Slide a new block into the space. Fill any gaps that remain between the mortar and the new block by pressing more mortar in with the end of your trowel. Flatten the joints with the trowel so they are flush with the face of the wall.
- 3
  Fill cracks in mortar joints either by chipping out the mortar and replacing it or by filling the crack with any of a number of epoxy-based concrete repair products that are available at most home improvement stores. Squeeze the epoxy into the crack with a caulking gun, and allow it to cure for 24 hours before doing more repairs to the wall.

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