Truro and Cornwall Damp and Mould: Heating Gaps, Heavy Rain and Older Homes

In Cornwall, 3.5% of households have no central heating, more than double the England rate of 1.5%. Add 1,019 mm of rain a year at the nearest Met Office station, St Mawgan, about 12 miles from Truro, and the conditions for damp and mould in older rented homes are clear. Truro is Cornwall's only city and its county town, with a Georgian and Victorian core, but the figures below cover the whole of Cornwall, so they describe a large, mostly rural area.

Cornwall in numbers

• Private rented households: 19.7% (England 20.5%); social rented: 12.8% (England 17.1%)
• Terraced homes: 21.9% (England 23.0%); flats: 11.9% (England 21.4%)
• Homes with no central heating: 3.5% (England 1.5%)
• Overcrowded households: 2.1% (England 4.4%)
• River or sea flood risk: 2.4% (England 1.9%); surface-water risk: 2.8% (England 5.9%)
• Rainfall: about 1,019 mm a year at St Mawgan, roughly twelve miles away

Why does the heating figure matter so much?

Condensation forms when warm, moist air meets cold surfaces. With low overcrowding, the moisture load per home is not the main problem; the cold is. Homes without central heating rely on fires, portable heaters or a single room being warm, so walls in the rest of the house stay cold. Mild, wet weather can also tempt tenants to keep windows closed, which traps moisture indoors.

Heating, EPCs and the minimum standard

Landlords should also check energy performance. Minimum energy efficiency standards currently stop most private lets in England being rented out below an EPC rating of E, and a poorly insulated, unheated home is both a compliance risk and a damp risk. A fixed heating system and decent loft and wall insulation tackle both at once.

Rain on older walls

Over a metre of rain a year puts constant pressure on older stone and brick, so gutters, flashings, pointing and roof coverings need regular attention. Surface-water risk is below the England figure, so the more common route for water is down and through the building envelope rather than up from flooding.

What landlords must do

The Homes (Fitness for Human Habitation) Act 2018 requires a rented home to be fit to live in, and Cornwall Council can assess damp and mould under the Housing Health and Safety Rating System.

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 Truro damp and mould page, and see the council's damp and mould complaints page.