Rust stains on inside of foundation walls

Cause

Poor quality concrete absorbing water which rusts the reinforcing, which in turns causes concrete to spall or crack allowing in more water 

Repair

  • for small areas of concrete damage, (150–200 mm2 maximum), remove enough concrete to expose steel that has no rust; sand to remove rust from the affected reinforcing; prime reinforcing with zinc-rich primer and a metal primer; repair hole with a sand-cement plaster
  • for larger areas of damage, or where little or no reinforcing remains, obtain advice from a chartered professional engineer on repair options

Cause

Reinforcing installed too close to the outer surface of the concrete

Repair

  • for small areas of concrete damage, (150–200 mm2 maximum), remove enough concrete to expose steel that has no rust; sand to remove rust from the affected reinforcing; prime reinforcing with zinc-rich primer and a metal primer; repair hole with a sand-cement plaster
  • for larger areas of damage, or where little or no reinforcing remains, obtain advice from a chartered professional engineer on repair options

Cause

Low strength concrete 

Repair

  • for small areas of concrete damage, (150–200 mm2 maximum), remove enough concrete to expose steel that has no rust; sand to remove rust from the affected reinforcing; prime reinforcing with zinc-rich primer and a metal primer; repair hole with a sand-cement plaster
  • for larger areas of damage, or where little or no reinforcing remains, obtain advice from a chartered professional engineer on repair options