How to Patch Cinder Block Holes

Learn the trick to patching a hollow cinder block.

You, yourself, can patch a hole in a cinder block of your house or garden wall. A hole in your house foundation is a perfect "doorway" for bugs and rodents to enter your home. And a hole in the house foundation or a garden wall is just plain unsightly.

Things You'll Need

• Protective eyewear
• Hammer
• Newspaper or expanding foam
• Mortar cement
• Bucket
• Trowel
• Construction sponge

Instructions

1. Put on protective eyewear.

2. Tap the cinder block with a hammer around the damaged area to remove loose pieces. Pry broken pieces from the opening of the hole, if necessary. It's fine to leave these loose pieces inside the block.

3. Remove dirt and debris from around the hole, for the best results.

4. Because cinder blocks are hollow, create a "backing" by filling the hollow, so the mortar has something to bond to. Small holes can be filled with newspaper. Large holes should be filled with an expanding foam fill. Let the foam dry for 24 hours; then remove 1 inch of the foam.

5. Pour dry mortar mix into a bucket. Add a little water and stir with a trowel. Continue to add water until you've added just enough to eliminate all dry spots. It should be just wet enough to be sticky and stiff enough to stay in place when drawn into a peak.

6. Dampen the area around the hole with a garden hose or a construction sponge dipped in water. Mortar bonds best to a wet cinder block, which will prevent the finished patch from falling out after it is dry.

7. Push the mortar into the hole, being careful not to shove the backing into the hollow of the block. Blend the mortar into the original block with a sponge while it is still wet.

Tips & Warnings

• Let the foam fill dry for twenty four hours before removing the excess.

• Wear safety goggles when using the hammer

References

• Difference Between: Difference Between Cement and Mortar