Crack(s) in foundation walls

Cause

Settlement due to ground subsidence or shrinking/expansion of clay soils

Repair

  • monitor the width of cracks for a period of time (approximately six months):
    • if they do not change, seal with a flexible exterior grade sealant
    • if they continue to get wider, obtain a chartered professional engineer’s advice on repair options

Cause

Insufficient depth of footings for ground conditions

Repair

  • monitor the width of cracks for a period of time (approximately six months):
    • if they do not change, seal with a flexible exterior grade sealant
    • if they continue to get wider, obtain a chartered professional engineer’s advice on repair options

Cause

Poor quality concrete or insufficient concrete cover of the reinforcing steel resulting in corrosion of the reinforcing causing the concrete to crack 

Repair

  • for small areas of concrete damage (150–200 mm2 maximum), remove enough concrete to expose non-corroded steel; sand to remove rust from the corroded reinforcing; prime the reinforcing with zinc-rich primer; repair hole with a sand-cement plaster
  • for larger areas of damage, obtain advice from a chartered professional engineer on repair or underpinning options 

Cause

Frost damage – water that gets into small cracks in concrete expands as it freezes, enlarging the cracks

Repair

  • monitor the width of cracks for a period of time (approximately six months):
    • if they do not change, seal with a flexible exterior grade sealant
    • if they continue to get wider, obtain a chartered professional engineer’s advice on repair options

Cause

The wall has been undermined by basement excavations

Repair

  • monitor the width of cracks for a period of time (approximately six months):
    • if they do not change, seal with a flexible exterior grade sealant
    • if they continue to get wider, obtain a chartered professional engineer’s advice on repair options