Constructed in spring 2021, this property was supposedly built to a higher tan modern insulation standard. However, by the following autumn, significant issues emerged. Dampness and mold has crept up walls, necessitating the disposal of clothing and bags stored within a wardrobe.
In conclusion, from the data loggers
- The surface relative humidity is constantly too high.
- Much of the vapour is still coming from the bathroom, despite the improve ventilation there. Bathroom vents draw air from inside, so if the air inside is humid, so the bathroom air will continue to be humid.
- Even if the insulation was not defective, the ventilation is inadequate.
Evidence & Illustrations
Note two tings, one dust mites can cause allergies, they colonise in the same conditions as mould, but ere on the carpet, see recommendations. Also that the surface temperature will increase without furniture of cold walls. This approach does not address the root cause, but will minimise the risk of mould.
To keep the property dry
|Consider targeted insulation
|Ask to builders or their architects to remedy the defects with you insulation, then test for defects using thermal imagery when hot inside and cold outside.
|Bathroom extractor fan
|Ask the builders or their architects to replace the main bathroom fan with a continuous flow bathroom extractor fan, such as the Vent-Axia Extractor Fan With Humidistat & Timer or the Brookvent Airstream DMEV 100 HT. Make sure to keep the door closed, with a sufficient gap, 10mm is required for effective ventilation.
|Use a dehumidifier
|To manage relative humidity, especially when poorly ventilated, humid or cold, consider using a dehumidifier such as the PureMate 20L/Day Portable & Compact Dehumidifier with 6.5 Litre (£179.99 Refrigerant), Duux Bora Smart Dehumidifier (DXDH02UK £300 Refrigerant) or Meaco DD8L Zambezi (£260 Desiccant – optimal for colder environments) – all highly rated by Which!. There are numerous alternatives if these specific models are not available. When selecting a dehumidifier, prioritise factors like daily and tank capacity, low noise levels, the availability of a continuous drainage option, and ease of use for programming functions, over aesthetics and weight. The technology behind dehumidifiers is well-established and straightforward to produce, ensuring you can find a suitable alternative focusing on a minimum daily capacity of 20L and the presence of a continuous drainage feature.
|Keep objects away from walls
|Reposition furniture and open curtains away from walls, to improve flow of air from the radiator to damp walls.
|Use fan to expedite drying
|Direct a fan towards any damp areas to expedite the drying process.
|Mark improvements on damp walls with a pencil line or sticky note and use a moisture meter, such as the Dr. Meter Wood Moisture Meter 2 in 1 Pin & Pinless Multifunctional Water Detector £23.99 or similar damp meter, to log and monitor reduction to dampness in walls. By doing so, you will gain early confidence in these recommendations. Use devices like the ORIA Wireless Thermometer Hygrometer to monitor relative humidity and temperature near walls or ceilings, look to keep the dew point at or below the external temperature. The dew point is shown on the app (if not use https://mouldpoint.co.uk to calculate the dew point from humidity and temperature readings).
|When mould is dry, consider sanding it down and removing it with bleach or anti-mould foam. While I personally recommend HG Mould Remover Foam Spray, the effectiveness between brands is likely similar.
|Minimise dust mites
|Dust mites, which are primary causes of allergies, thrive in the same humid environments as mould. The best way to combat dust mites includes turning down duvets, airing out pyjamas, turning pillows daily, washing sheets regularly, turning mattresses, and vacuuming around cold walls weekly. Additionally, maintaining a lower humidity level in your home by using a dehumidifier can significantly reduce dust mite populations. Ensuring good air circulation and keeping the house well-ventilated are also key strategies. It is advisable to use allergen-proof mattress and pillow covers to create a barrier against dust mites. Cleaning upholstery, curtains, and carpets with a HEPA filter vacuum cleaner further helps in minimising dust mite allergens in the home.
|Target vapour from cooking
|Always use tops on pots and pans to reduce vapour emission by 80% and where applicable use an externally ducted kitchen extractor fan.
|Target vapour from clothes drying
|Opt for a tumble dryer, dry laundry in a well-ventilated room with the door closed (such as a bathroom with the extractor fan on or window open), or employ a sufficiently high capacity dehumidifier. Avoid drying clothes in poorly ventilated areas and anywhere near cold walls.
|Remedial actions – estimate of costs