Good Repair Guide: Leaking basement walls

Residential basements are common in houses built on sloping ground and can be valuable and useful spaces if they are dry and warm. In many cases, the use of a basement changes over time as household size, lifestyle and interests change. 

Work may be required to upgrade the space. High internal humidity, musty odours and efflorescence in below-grade basements are all signs that moisture may be entering the space through porous concrete retaining walls. 

This Good Practice Guide covers only basement walls of residential buildings on sloping sites that are no more than one storey in height below natural ground and not subject to hydrostatic pressure. Where a wall is subject to hydrostatic pressure from groundwater or a spring, seek specific design advice from a specialist damp-proofing company.