Damp and Mould Climbs the City Renter’s Complaint List

Damp and mould have moved up the list of things city renters worry about, and the reasons are partly economic. With energy costs front of mind, many residents heat less and seal more, which keeps warmth in but also keeps moisture in — and moisture is what mould needs.

The Air & Environment desk fields a steady stream of questions about black spots in bathroom corners and condensation streaming down cold windows. The pattern is familiar: a sealed flat, indoor laundry drying, showers and cooking adding humidity, and nowhere for that water to go but the coldest surface in the room.

Public-health bodies including the World Health Organization have flagged indoor damp and mould as a genuine respiratory concern, not merely a cosmetic one. But the everyday fixes are mostly behavioural: vent steam at the source, keep relative humidity in a moderate range, and don’t dry washing in a closed room.

The nuance worth holding onto is that not all damp is the resident’s fault. Where sensible habits don’t solve it, the cause is often structural — a leak, a cold bridge, poor building ventilation — and that’s a conversation for whoever maintains the building.