Damp Proofing Teddington

Teddington is a riverside suburb tucked between Bushy Park and the Thames, and its character comes from streets of Victorian and Edwardian terraces and semis built after the railway arrived in the 1860s. Around the High Street, Broad Street and the roads running down to Teddington Lock you find modest workers' cottages alongside larger double fronted villas, while interwar houses, mansion blocks and modern riverside flats fill in the gaps.

Most of Teddington's older homes have solid brick walls and suspended timber ground floors, and the faults we find are very consistent. The first is a bridged damp proof course. Over the decades, front paths, side passages and rear patios have been raised, often well above the original damp proof course, and water simply bypasses it. Rendered plinths that run down to ground level do the same thing.

The second is ventilation. The void beneath a suspended timber floor has to be ventilated through air bricks, and in Teddington these are frequently blocked by raised ground, side return extensions or later rendering. The result is humid air trapped under the floor, followed by wet rot in joists and wall plates, and in some cases dry rot. Because floors are covered, this can go unnoticed for years until boards start to feel soft or a musty smell appears.

Penetrating damp is the third common problem. Defective gutters and downpipes, worn pointing, cracked render and failed flashings around chimneys and bay roofs all let water into solid walls, particularly on the elevations that face the prevailing south westerly wind.

Then there is the river. Properties close to Teddington Lock, along the riverside and on the lower lying roads nearby sit on a higher water table, and cellars and lower ground floors can be damp throughout the year. Anyone thinking of converting one of these spaces needs a waterproofing design, usually a cavity drain membrane system with a sump and pump designed to BS 8102, rather than surface coatings that fail once water pressure builds.

Rear extensions are another regular source of trouble. New floor levels that sit higher than the original, poorly detailed junctions between new and old walls, and flat roofs with failed upstands can all let moisture into the older fabric of the house. We often find that damp blamed on the original house is actually coming from the extension.

In flats and in houses where windows have been replaced without trickle vents, condensation and black mould are the most frequent issues, especially in bedrooms and bathrooms during the winter months.

Teddington's period houses are always in demand, and when they come up for sale, mortgage valuers regularly flag damp or timber concerns that need a specialist report. Our pre-purchase damp and timber surveys explain what the readings mean in a solid walled Victorian house, separate genuine defects from the normal behaviour of older buildings, and set out a clear scope for any work. That gives buyers the facts they need to negotiate, and helps sellers resolve a concern quickly so the sale stays on track. Landlords letting older properties in TW11 also use our reports to show that reported damp has been properly investigated and dealt with.

Our surveys in Teddington use moisture readings, salt analysis and thermal imaging to separate these causes, so you only pay for the work your home actually needs. We cover TW11 and the surrounding area every week from our London office.