Damp-Proofing London Properties – What Every Homeowner Should Know

The UK has a wet climate, due to its location in Northern Europe and London sits on the Thames Valley Basin, which is clay based and holds moisture. We also have high rainfall and that means wet ground, where damp thrives and this causes damage to buildings if they are not adequately damp-proofed. If you think you have damp issues in your home, you can arrange for an independent damp survey and a certified damp surveyor will inspect the building and provide you with a detailed report.

Damp-proof course

Because the ground holds a lot of moisture, buildings need what is known as a damp proof course, which is a thick strip of bitumen-based material that is sandwiched between the lower brick courses. This acts as a moisture barrier, preventing damp from making contact with the materials above the DPC; without such a barrier, a building would succumb to damp very quickly, as moisture moves through capillary action. Bricks, mortar, render, masonry and timber are all impacted by moisture and in the event the DPC membrane is damaged or degrades, there is nothing to stop rising damp from damaging the walls, which would eventually penetrate into the internal walls, damaging plaster, wooden window and door frames.

Cavity walls

Most houses in London have cavity walls; an exterior wall with a space of 6-9 inches between the outer and inner walls and moisture can penetrate external walls and over time, it can affect the interior of the building. Of course, some areas have better drainage than others and buildings might not be impacted by ground moisture, yet driving rain can lead to penetrating damp and in some cases, this damages the structure.

Door and window frames

Timber frames are usually screwed into brickwork using wooden blocks to seat the frame and when a frame is fitted, a mastic or silicone sealant is pumped into the small gap between the frame and the walls to provide a watertight seal that stops rainwater from entering through that gap. Mastic would be used to seal the exterior, while silicone is used to seal the interior and if either seal is compromised, damp can penetrate the walls and damage the interior.

Waterproofing a roof

The roof is a critical component of a structure and it needs to be watertight for obvious reasons. Of course, when a building is constructed, the roof should be waterproof and regular inspections are advised to give you a heads-up if a leak develops. Missing roof tiles are a common cause of leaks, which is why you should inspect the roof after a storm, as gale-force winds can lift roof tiles. Guttering needs to be kept free of obstructions to prevent a water overflow.

If you are planning to buy a house in London, you need to contact London Damp Specialists on 020 7205 4886 or complete the online survey booking form that is found on this website. Don’t take any chances when it comes to damp, mould and timber rot, call in a damp expert today and get a definitive answer.