Protect Your Foundation: Repair The Damage To Your Basement Walls

Posted on: 3 December 2014

If you have a basement, chances are the support walls are constructed of concrete blocks, which are held together with a concrete mortar. Over time, that mortar can decay. When that happens, you'll begin seeing gaps in the concrete between your concrete blocks. Those gaps should be repaired as quickly as possible, to preserve the structural integrity of your foundation. If the gaps are small enough, you can repair them yourself.  

Remove The Damage

Before you begin this portion of the process, you'll need to gather a few supplies.

  • 1" wide concrete chisel
  • Hammer
  • Large paint brush
  • Safety goggles
  • Heavy duty work gloves


  1. To protect your hands and eyes, put your safety goggles and work gloves on.
  2. Use your 1" chisel and hammer to carefully chisel away the damaged areas of the mortar.
  3. Be careful not to damage the surrounding concrete blocks.
  4. Use the paint brush to dust away dirt and debris from the chiseled areas.
  5. You're now ready to begin repairing the damage.

Mix The Mortar

The next thing you'll need to do is mix the fresh mortar.

Supplies You'll Need

  • Masonry cement
  • Fine sand
  • 5 gallon bucket or wheelbarrow depending on the amount of mortar you'll be mixing
  • Water


  1. Combine 2 parts masonry cement and 6 parts of fine sand in a wheelbarrow or 5 gallon bucket.
  2. Add enough water to form a moist paste.
  3. Continue mixing until your mortar is the right consistency.

Repair The Damage

Now that you have the area prepped and the mortar prepared, you're ready to begin repairing the damage.

Supplies You'll Need

  • Work gloves
  • Pie-tipped trowel
  • Brick jointer


  1. Place a medium scoop of mortar onto the end of trowel.
  2. Working in one direction at a time, either horizontal or vertical, press your trowel up against the damaged areas and rub the mortar into the spaces.
  3. Smooth the mortar down to pack it into place.
  4. Continue working in either a vertical or horizontal pattern until all those spaces are filled.
  5. Move on to the remaining spaces until all the spaces are filled.
  6. Use your brick jointer to press the mortar firmly into place and to smooth the lines.

To keep your basement and foundation in good repair, you should inspect your basement and foundation at least once every six months. Repair any damage as soon as you find it. For more information, or if you would like professional assistance, contact Reynolds Construction or a similar company.