Typical signs
- White powdery deposit, peeling paint, damp concrete or cellar odour.
- Vertical tracks on the foundation wall or a wet floor at the perimeter.
Where it is often found
- Basements, crawlspaces, garages and retaining walls.
What it can mean
- Poor surface drainage or mismanaged gutters/downspouts.
- Crack, weak joint, temporarily high water table or deficient waterproofing/perimeter drainage.
What to check next
- Observe during or after rain.
- Check grading, downspout discharge, window wells and cracks.
- Confirm whether the slab or lower wall remains damp by touch or moisture test.
Reasonable immediate actions
- Move water away from the building, remove wet finish materials applied directly to concrete and dry the area.
When to stop and call a professional
- Major infiltration, hydrostatic pressure, structural cracks, extensive mould or a need for excavation.
Prevention
- Positive grading, functioning gutters, extended downspouts, humidity control and assemblies suitable for concrete.