Bristol Damp and Mould: Surface Water Risk, Hills and Solid Stone Walls

The number that stands out in Bristol's data is surface-water flood risk: 14.8% of properties are at medium or high risk, about two and a half times the England figure of 5.9%. Bristol is a hilly city, and rainwater running downhill towards older terraces is a recurring source of damp for landlords and tenants alike.

Bristol in numbers

• Private rented households: 26.2% (England 20.5%); social rented: 18.7% (England 17.1%)
• Terraced homes: 32.1% (England 23.0%); flats: 33.9% (England 21.4%)
• Homes with no central heating: 1.6% (England 1.5%)
• Overcrowded households: 5.1% (England 4.4%)
• River or sea flood risk: 2.2% (England 1.9%); surface-water risk: 14.8% (England 5.9%)
• Rainfall: about 819 mm a year at Filton, roughly five miles away

Hills, surface water and stone walls

Bristol has a large stock of Georgian and Victorian terraces, especially in Clifton, Redland and Totterdown, many with solid stone walls and no modern damp-proof course. Combine that with steep streets and the surface-water figure, and the usual causes are on the outside of the building. A landlord's checklist for a hillside terrace:

• Gullies, drains and gutters that carry water away from the walls
• External ground that slopes towards the building or sits above internal floor level
• Retaining walls, lower-ground and basement rooms that sit against banked earth
• Pointing and render on elevations that face the prevailing rain

Flats, HMOs and condensation

A third of Bristol's homes are flats and the city has two universities, so shared houses and converted flats are common. Overcrowding at 5.1% is above the England rate, which adds moisture indoors. In older conversions with poor extraction, condensation and mould become a recurring dispute even where the structure is sound.

How the council grades damp and mould

Councils assess hazards under the Housing Health and Safety Rating System, which scores them into bands. Bristol City Council has a statutory duty to act on damp and mould hazards rated Band A to C, the most serious category, and in practice also takes enforcement action on Band D. If a landlord does not investigate after being told, the council can serve an improvement notice requiring the cause to be fixed, not just redecorated over.

What landlords must do

The Homes (Fitness for Human Habitation) Act 2018 requires a rented home to be fit to live in. Investigate promptly, fix the cause, and keep a dated record of what you found and did.

Awaab's Law currently applies to social housing, with private landlords expected to follow. Our guide to Awaab's Law and the private rented sector explains the current position.

To find a specialist, see our Bristol damp and mould page, and read the council's guidance on damp and mould.