Rust stains on concrete/concrete block foundation walls
Listed under: Exterior, concrete and cement, concrete blocks, metal, steel, stains, foundation walls, walls, moisture, durability, corrosion, rust
Cause
Poor quality concrete absorbing water that rusts the reinforcing, which in turns causes the concrete to spall or crack, allowing in more water
Repair
- or 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 the 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
The reinforcing was 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 the 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
The building is close to the sea and the concrete is of poorer quality
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 the 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
The concrete is low strength
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 the 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
Moisture is rising up from the ground
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 the 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