Salisbury Damp and Mould: Five Rivers, Groundwater and Rising Damp

Salisbury is a cathedral city with a core of medieval and Georgian buildings, built on low-lying land near the confluence of five rivers. The official figures are for the whole of Wiltshire, a large mostly rural county, so they look benign: river and sea flood risk of 1.1% is below the England figure of 1.9%. The more useful question for a city landlord is what the water table does to old buildings.

Wiltshire in numbers

• Private rented households: 17.4% (England 20.5%); social rented: 14.5% (England 17.1%)
• Terraced homes: 20.7% (England 23.0%); flats: 11.0% (England 21.4%)
• Homes with no central heating: 1.0% (England 1.5%); overcrowded households: 1.8% (England 4.4%)
• River or sea flood risk: 1.1% (England 1.9%); surface-water risk: 3.5% (England 5.9%)
• Rainfall: about 783 mm a year at Boscombe Down, roughly seven miles away

Averages hide the city

A county-wide percentage averages a city on a river floodplain with downland, villages and farmland. Do not read Wiltshire's low figures as a guarantee for a property by the water meadows. A landlord's own site knowledge, and any flood history, is worth more than the headline number.

Groundwater and rising damp

Low-lying land near several rivers means a high water table in wet periods. Older buildings with no damp-proof course, or with one that has failed or been bridged, can draw moisture up through the walls, leaving tide marks, salt deposits and flaking plaster at low level. It is worth knowing the signs that separate rising damp from condensation:

• Rising damp stays low, usually below about a metre, and leaves a tide line
• Condensation appears on cold surfaces, such as corners, window reveals and the tops of walls
• Rising damp is worse in wet winters; condensation follows heating and cooking
• Both can be present at once, so a survey with moisture readings beats guessing

Heritage buildings

Medieval and Georgian properties are often listed or in a conservation area, so check consent before work and use breathable repairs suited to traditional construction. That limits the options but not the duty to provide a home free from serious damp.

What landlords must do

The Homes (Fitness for Human Habitation) Act 2018 requires a rented home to be fit to live in, and the 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 covers the current position.

To find a specialist, see our Salisbury damp and mould page.