A guide to identifying and treating damp in the home.
Damp is one of the most common problems that can occur in your home. It is important to know how to identify it and treat it properly – both for the upkeep of the property and for your own health.
There are three main types of damp: condensation, rising damp and penetrating damp. Each has unique traits and requires different treatment methods.
The most common form of damp is condensation. When the air outside is colder than that inside, the latter will condense, forming droplets that typically appear on walls and windows. Usually you’ll see condensation form in the kitchen or bathroom as these are the rooms that generate the most moisture. Rooms where people sleep or where laundry is hanging are also susceptible.
As well as water droplets, other signs of condensation include dark mould and an unpleasant smell. Asthmatics or anyone with a respiratory issue may be particularly sensitive to these effects. If left untreated, condensation can damage paint, plaster and window frames.
If you notice condensation forming in your home, the best treatment is also the simplest: wipe the water droplets away with a cloth. There are many more ways to prevent condensation, however. Opening windows and properly ventilating your kitchen and bathroom are essential, especially in the winter months. Having fans in both rooms can also be very effective.
Since condensation forms when the air outside is significantly colder than that inside, it’s a good idea to monitor your heating use. Keeping your heating on at a constant, low or medium temperature is much better than alternating between off and then on at a high temperature (make sure you check into how this can affect your heating bill and home emissions). Having a consistent temperature reduces the risk of condensation. Dehumidifiers are also a good preventative measure, especially in rooms where you hang laundry to dry.
As its name implies, this occurs when water comes through the floor or rises up a wall. The main symptoms include tide marks on the wall, damaged skirting boards, peeling paint or wallpaper and wet patches. On occasion you may also see a white powder form.
Most homes are built with barriers to prevent ground water from seeping in, although older buildings may lack these, so it’s a good thing to check when purchasing such properties. There are two types of damp-proof barriers: a damp-proof course, which is a strip of bitumenised felt or plastic that sits in the wall; and a damp-proof membrane, which is a sheet that connects to the damp-proof course and is laid under the concrete foundation. These barriers form a seal to prevent rising damp.
If you are experiencing rising damp, it’s best to contact a surveyor to assess the cause. In many cases, there may be a drainage issue in your area that will mean the ground water level rises above the barriers. A surveyor would be able to assess the source of the problem and advise you on the best course of action, which could include adjusting the space below the floorboards so water can evaporate, improving local drainage or ensuring the ground slopes away from your home so water won’t collect near walls.
Penetrating damp refers to any water that leaks through a wall, roof or ceiling. Unlike rising damp, penetrating damp travels horizontally rather than up. The main symptoms include damp patches on the walls and ceilings, large bubbles in the plaster or paint, and, if it is left untreated, holes in the ceiling.
Generally speaking, penetrating damp occurs because of a leak, whether due to plumbing or a structural problem. If the symptoms worsen when it rains, then the cause is likely to be faulty guttering, cracks in the walls or spaces in the roofing. Otherwise, the issue is probably caused by a leak in a pipe.
As with rising damp, the best way to treat penetrating damp is to speak to a surveyor, especially if you are unable to identify the source of the leak. For those living in flats, you should also contact your neighbours to see whether they are experiencing leaks or similar symptoms, as this can help narrow down the causes.
Image: Erin Perry