How to combat mould and condensation in tenanted properties
Winter is a challenging part of the year – people spend more time indoors and lower temperatures do not encourage keeping windows open or at least ventilating properties frequently. 2020/21 winter may be even more difficult due to COVID-19: everybody is encouraged to spend more time at home and it will translate into higher condensation levels. Human bodies produce moisture (breathing, exercising indoors, cooking, showering, washing up etc.) which will need to be extracted from the property, otherwise, it will start condensing on the coldest surfaces (windows, corners, external walls). The next stage is mould growth – damp walls are an excellent environment for mould to grow.
Signs of condensation:
- Water condensing on the inside of windows or window sills
- Water collecting on tiles
- Black mould dots spreading from corners and then all-over external walls and skirting boards.
- Black mould growth on silicone seals
How is moisture extracted from flats?
- Air bricks/wall vents
- Opening windows
- Keeping window air trickle vents open
- Extractor fans in kitchens and bathrooms
- Mechanical ventilation systems
In some countries, like Germany, lease agreements stipulate that tenants need to air their properties at least twice a day. Some tenants in Scotland are not willing to air their properties as they believe that opening windows will reduce the indoor temperature and increase their heating bills, however, this is a misconception. If moisture is kept inside and not allowed to be removed, your heating system will not only heat the walls (the most important part of heat retention system) and air but also the water in the air which is very inefficient and expensive in the long term.
Condensation and mould tenant advice
- Keep your home well ventilated by opening windows every day and keeping drip vents open to allow the moist air to escape.
- Try to keep indoor temperature constant – when the temperature drops, dew point drops with it and the moisture in the air starts condensing. The lower the indoor temperature, the lower the dew point, and it means more condensation.
- Always turn the extractor fans on in the kitchen when cooking to allow them to extract any excess moisture. Please consider opening windows for extra extraction. Keep the lids on pots while cooking.
- Open windows and leave extractor fans on after having a bath/shower – keep the bathroom door shut to prevent moisture spreading to other rooms.
- Dry clothes outside or, when done inside, open windows in the room used for drying. Consider buying a condenser tumble dryer that does not need an extraction pipe.
- Please leave small gaps between furniture and walls to allow air circulation.
- Do not block air bricks or other types of air vents.