Damp and condensation are some of the most common complaints of homeowners and tenants in the UK. It is suggested that as many as 1 in 5 domestic dwellings suffer from excess moisture, which leads to damp and condensation in lofts and attics, and the problems that follow.
As many buildings are now well designed to retain heat and keep external air out, with effective building insulation and double-glazed windows, humidity is often trapped, with nowhere to go but up. When the indoor air makes its way into lofts and attics, condensation can form on the colder surfaces.
Many factors contribute to the humidity that can cause damp problems and condensation in your loft or attic. The UK has a humid climate in general, and the average relative humidity can range from around 50%-60% in the Spring and Summer, to as high as 80%-90% in the Autumn and Winter. Also, cooking, bathing, laundry and other day to day tasks can release more than 14 litres of water vapour into the air each day. Steam and heat from hot water tanks can also be a factor, especially if they are installed in the loft space.
If left unmanaged, excess moisture and condensation in your loft can penetrate walls, ceilings, plasterboard, wood and other hygroscopic materials. Lofts and attics are often unheated rooms, so they can be much colder than the rest of the building, especially during the colder months when central heating is used regularly. If the floor of the loft and the roof are insulated, these spaces can be even colder. Due to this difference in temperature, any warm, humid air that gets into the loft - usually through gaps in insulation or loft hatches - condensates on any cold surfaces, forming small deposits of water.
The most common consequence of condensation and damp in lofts and attics is dark patches, mildew and mould. Over time, these issues can spread throughout the area. They do not look good, make the air feel unpleasant, and lead to bad odours. You might consider these issues superficial and something that can be easily ignored, but they can also affect your health. Mould produces spores, allergens, irritants and even toxins. The presence of mould can cause or aggravate respiratory problems, allergies, headaches, skin problems and more.
When moisture and mould take hold, they can result in severe structural damage. They can warp timber elements, rust metal and weaken concrete. In the worst cases, battens and joists can rot and deteriorate. When this happens, roofs can let in water, become unstable and pose a risk of collapse. The repair of any architectural damage to a property can be expensive and time-consuming, especially if it is unexpected.
For many families, the loft is a storage space that you only go into on a few occasions each year. If you have problems concerning humidity, excess moisture and condensation in your loft, then all stored items are at risk of being damaged. Documents, photographs, other personal items of significance, furniture, electronics, equipment and artwork, are all vulnerable to water damage, and even if they are not expensive, they may be valuable.
There are a few practical measures you can take to stop the occurrence of condensation and other excess moisture in your loft. You might need to make changes to improve ventilation, such as adding new vents. If you already have vents, make sure that they are not covered by boxes, carpet, spare tiles or anything else. You should also replace any cracked or broken roof tiles, as they could be letting in rainwater and other elements.
If you have checked the area and have done everything you can do to prevent a build-up of excess moisture but are still noticing signs of humidity damage and condensation, you might need to implement a dehumidifier.
Refrigerant dehumidifiers use a system of fans, refrigerated coils and heating elements. They draw humid air in, pass it over the cold coils to lower its temperature below the dew point and cause the water it holds to condensate. The condensate drips off into a tank or outlet, while the dried air is heated and recirculated to collect more moisture.
Desiccant dehumidifiers use a system of fans, a reticulated mesh of absorbent material on a rotary wheel and a heating element. They draw humid air in and pass it through the desiccant wheel so it can collect moisture. As the wheel turns, a section of it is heated, so that any water it absorbed can be removed as vapour, and the dried air is recirculated around the space.
Refrigerant dehumidifiers work well in areas of high humidity and when temperatures are above freezing, around 5-30℃. A refrigerant dehumidifier would be ideal for a loft or attic that does not tend to be too cold at any time during the year.
Desiccant dehumidifiers are more effective in colder temperatures and can work in temperatures below 0℃. A desiccant dehumidifier would be perfect for a loft or attic that is considerably colder than the rest of the property. These units need to vent water vapour out of the space - by use of ducting or exhaust, so access to the outside is required.
Both refrigerant and desiccant dehumidifiers give out heat, which can war the area slightly. The heated air can collect more moisture so that the units can collect it more efficiently. However, desiccant units do tend to consume more energy than refrigerant models, so they are more expensive to run.
We have an excellent range of domestic dehumidifiers for lofts and attics available. The Dantherm CDF 10 and the Aerial AD110 are wall-mounted, refrigerant dehumidifiers that can be installed permanently. The CDF 10 gravity drains the condensate and features a water hose connection that can be led outside or into a drainage system. You can also purchase an optional 5.5-litre water tank, but remember that will need to be emptied regularly. The AD110 has an automatic condensate pump so that the collected water can be forced out of the space via a hose, even if it has to travel upwards. If you only need a temporary drying solution, The EBAC CD35 and the Master DH 26 are both portable dehumidifiers, with convenient handles and vast operating temperature ranges.
If you have a cold loft or attic and require a desiccant dehumidifier, The Ecor Pro DH800 and DH1200 have an operating temperature range of -20℃ to +40℃. Both units are compact and lightweight, can be installed into confined spaces, and they work at any angle. These dehumidifiers are also ductable so that you can vent the vapour they extract directly out of the area.
View our Best Loft Dehumidifiers.