What to do about condensation in your building

Moisture is almost aways present in the air around us, but there are times when too much of it can lead to water building up on cold surfaces. Condensation might only be a mild inconvenience sometimes, but it can become a serious problem if there’s an underlying fault that’s causing it.

This blog explains what you should know about condensation in buildings, from the causes and signs to the consequences if you leave it uncontrolled – and how a building warranty could help.

What causes condensation in buildings?

Condensation occurs in humid environments, when excess moisture in warm air comes into contact with a cold surface and condenses into visible water droplets. This is commonly seen on glass windows when it’s cold outside, and sometimes mistaken for a leak when it forms on walls.

If there is excess water vapour in the air, it’s likely that there are problems with ventilation and insulation. Condensation will form when there is nowhere for the moisture to escape to, or if there is a significant temperature difference between the inside and outside of a wall or window.

It’s not unusual for condensation to occur in newly built homes, as the construction materials may still be drying out. The water in concrete, mortar, plaster, and paint can take several months to evaporate fully, but this is a normal process that should resolve itself within the first year.

When a property is occupied, many everyday activities can contribute to excessive moisture lingering in the air. Cooking, cleaning, showering, washing and drying clothes – even just breathing increases moisture levels. Habits like having lots of plants, using humidifiers, and pushing furniture against exterior walls don’t help, either.

Condensation is only caused by a building defect if there are inadequate ventilation or insulation measures, or if there are faults in the roof, walls, or window and door seals that allow water ingress.

What are the signs of condensation?

Condensation is constantly forming everywhere on some level, but may not even be noticeable most of the time. Serious signs of condensation that you should look out for include:

• Water droplets forming on windows, walls, mirrors etc.
• Wet or water-stained corners of window frames (visible rot if made of wood)
• Damp walls with patches of peeling wallpaper or blistering paint
• Musty smells around the property (stronger near windows and exterior walls)
• Mould forming on windowsills, walls, curtains, carpets etc.

If you see a ‘tide mark’ of damp on a wall, this is not condensation, and is more likely to be caused by rising damp from the ground or penetrating damp from structural defects or plumbing issues.

Is condensation in buildings dangerous?

If left unchecked, consistently excessive condensation can cause a number of problems for both buildings and the wellbeing of their occupants. Even on ‘waterproof’ surfaces that are designed to withstand water, such as uPVC window frames, a constant build-up of sitting water can lead to the growth of mould.

When the moisture dries, paint, varnish, and wood trims can crack, peel, and split. This can erode seals over time, reducing insulation and leading to moisture ingress from outside, which will continue to exacerbate the problem. Carpets and furnishings can also begin to rot from retaining too much moisture.

Condensation and damp can also cause various illnesses, especially if black mould begins to grow. Some common health issues resulting from this include breathing problems and skin irritation, with symptoms ranging from rashes and itchiness to runny noses and wheezing. The worse the problem gets, the more serious the symptoms will become.

This is why it’s so important to investigate condensation and address its cause before it’s too late, keeping your home standing strong and your family in full health.

How to control condensation in buildings?

Even in the case of a new build ‘drying out’, there are still ways to ensure that your property achieves balanced moisture levels and reduce the risk of constant condensation. The key is to reduce moisture production and increase ventilation wherever you can.

Changing your habits to keep everyday moisture levels as low as possible can include:

• Avoiding leaving damp clothes to dry indoors (e.g. on radiators or clothes horses)
• Doing full loads of laundry as needed instead of constantly running the washing machine
• Not taking long showers or frequently running baths (and keeping the bathroom door shut)
• Making sure that extractor fans/cooker hoods are on while showering/cooking
• Opening windows to let fresh air in if the room is too humid (or using a dehumidifier)
• Moving furniture and clutter away from the walls to improve air flow
• Keeping the property evenly well-heated, especially during colder months

Of course, the best way to manage condensation in buildings is to make sure that there is adequate ventilation in every room. Kitchens and bathrooms in particular should have extractor fans to handle the higher levels of humidity produced in these areas.

Windows and doors must be properly fitted and sealed to ensure proper insulation and energy efficiency, but it can also help to have small ‘trickle vents’ that allow small amounts of air to circulate through the building envelope. This is also more affordable than installing a mechanical ventilation system to extract humid air and replace it with cooler air from the outside.

Another way to make sure that the building is sufficiently ventilated from the start is to have a thorough inspection confirm that the property has been fitted with appropriate measures such as soffit ventilation, a breathable roof membrane, and subfloor ventilation under suspended floors.

Do building warranties cover condensation?

If you have a building warranty in place that covers your property against the costs of structural defect repairs for 10 years or more after completion, you may be able to make a claim for condensation damage if faulty workmanship or materials are behind the condensation problem.

This typically involves inadequate insulation or ventilation being installed during construction, which may not become apparent until several months later as the condensation keeps getting worse. On the other hand, excess water that you may initially think is condensation could be a result of water ingress and damp, which may also be due to a similar structural fault.

Damp and condensation will therefore only be covered by a structural warranty if the builder or developer is at fault. During the first 2 years of cover, the builder may be held directly accountable for carrying out repairs, whereas you must go through your warranty provider to arrange corrective work after this initial period.

The point of a building warranty is to reduce the risk of this happening, ensuring that construction work is monitored from the beginning to completion by experts who can identify problems as they occur and recommend fixes before they can get any worse.

If you’re looking for a building warranty provider to make sure that your new build property is correctly insulated and ventilated, then we can help. Our ABC+ Warranty is upheld by specialists who have been inspecting buildings since 1989 and are registered with the RICS (Royal Institution of Chartered Surveyors).

To discuss your structural warranty needs or to request a quote, call our team on 0161 951 5707, or send us an email at info@architectscertificate.co.ukand we’ll be in touch soon.