Damp Proof Course: Why Every London Home Needs DPC

Damp Proof Course: Why Every London Home Needs DPC

3rd July, 2025

The UK has a wet climate, which is typically unpredictable, with rain and cloud being the norm and this is an ideal environment for damp and mould to attack London homes. In this short article, we take an in-depth look at damp proof course and why every London property must have this essential moisture protection barrier.

What is damp proof course made from?

If a property was built pre-1970s, the DPC would be made from bitumen, which degrades over the years, while post 70s properties should have a heavy-duty type of plastic that is much more durable. When a house is under construction and the footings are completed, the damp proof course in sandwiched between the first courses of bricks and this is an impenetrable barrier that stops moisture from attacking the building.

Rising damp

This is moisture that comes from the ground and if it should be able to jump the DPC membrane, damage is sure to occur. Damp moves with capillary action, much like a sheet of paper when a corner is put into liquid, slowly getting into brickwork, masonry, mortar and timber. If not addressed, damp can spread to the interior walls and that means high repair costs; when buying older properties in London, never assume there are no damp issues, especially if there is a basement/cellar.

Signs of rising damp

If you see any of the following, damp is more than likely present;

  • Crumbling brickwork, masonry, mortar or render.
  • Exterior mould and moss growth.
  • Damp patches on interior walls or ceilings.
  • Fungal growth on window or door frames.
  • Tide marks on walls.
  • Peeling wallpaper & bubbling paint.
  • Discoloured plaster or timber.

If there is a dank, musty smell in the house, mould won’t be far away; investigate with a flashlight or better still, call London Damp Surveys on 0207 305 5997 and we’ll get to the bottom of your damp issue with an accurate survey.

DPC treatments

Aside from the traditional damp proof course, DPC injection is a very effective way to prevent rising damp; we have many years of hands-on experience in assessing damp in London properties.

Wet ground

Some areas of the capital have clay and bedrock and this retains water; low lying areas are particularly vulnerable to rising damp; older buildings need constant monitoring and if you are thinking of acquiring an older London property, we can do a damp survey and you receive a detailed report within a day or two. Our qualified surveyors use cutting-edge equipment to determine the status of your London home.

Regular inspections of the exterior, close to ground level, looking for signs of damp; check your loft every few months, take a flashlight and inspect joists and rafters. A leaking roof can wreak havoc on the timber structure and wet rot can set in.

We are a family-run business that has been serving London and surrounding areas for years, providing accurate damp and mould surveys. Contact us for a speedy assessment of your home.