Damp Bathroom?

If you have a small bathroom, or one without opening windows, or have a number of people using it, you'll probably be familiar with the dampness problems that can arise.


Dampness in bathrooms can lead to mould and mildew, which can exacerbate respiratory disorders, and of course lead to frequent redecoration and cleaning.


An extractor fan can sometimes be the solution to this. However, let's take a moment to properly understand what causes the problem in the first place.


Water vapour can be carried by air. When you breathe out, you breathe out some water vapour; usually, this is carried away in the air.


However, cold air can hold less water vapour than warm air. If you breathe out onto a mirror or pane of glass, your breath cools down, and as it does so, water condenses out of the air, forming droplets.


The same thing happens in your bathroom. A warm shower will warm the air, whereupon it will carry the maximum amount of water vapour it can - the air is said to be saturated with water vapour. However, as the air cools down, the water has to go somewhere - it condenses onto cold surfaces, such as walls, ceilings and mirrors. This is the cause of your damp problem.


Consequently there are a few things to consider when solving the damp problem.


  1. Keeping the room warm will help. If there are cold spots in the room, they are most susceptible to dampness. If you have problems with the insulation of the room, you'll have more problems with dampness. With a persistent (chronic) dampness problem, you may want to engage the services of a thermographic surveyor, such as iRed, who can use sophisticated infrared camera equipment to work out exactly what is wrong with the structure of your building - such as faults in insulation, or cold air ingress.
  2. Reducing the water content in the air will also help. If there are 5 people in the house, all having long, hot showers every day, it will be harder to combat the dampness.
  3. All domestic buildings are designed to promote airflow through their structure, to allow damper air to exit the building, and drier air to come in. If you have blocked off all the paths for ventilation in your house, you will have a damp problem.


Having considered all of this, you may want to just open your bathroom window and turn the radiator up a bit. If the problem persists, or you don't want to pay the extra heating costs, consider an extractor fan.


Simply, an extractor fan pumps moist air out of the room, allowing drier air to be sucked in from the rest of the house. Without moist air, there is no water to condense onto cold surfaces.


BS7671 electrical wiring regulations specify a particular rate of extraction needed in a bathroom. We've seen inadequate fans fitted by other electricians which have cost money but make no difference to the damp problem, because they don't extract enough air.


Fans should also operate on a timer, so that they continue to extract after the bathroom has been used, perhaps for five to ten minutes. Tuning this timing is important to maximise effectiveness. Having a fan that goes off as soon as the light goes off (we've seen this too) is a waste of effort.


Some modern extractor fans also have a humidity sensor, which means they will cut in and out depending on the humidity of the air in the room. This is perfect for a bathroom situation, as the fan will always be working to minimise dampness, and won't be working unnecessarily (for example when the bathroom is dry and somebody has just used the toilet.)


Finally, the current trend in extractor fans is noise reduction. Rather than having a jet engine on the wall, the latest fans are whisper-quiet and won't be heard from elsewhere in the house.


If you think an extractor fan is the solution to your dampness problems, or if you simply want to discuss all the options, do contact us to arrange an appointment.

Any questions?

Devonia Electrical
13 Shute Park
Malborough, Devon TQ7 3SU


Tel: 01548 561561

Mobile: 07970 062008

Email: david@devonia-electrical.co.uk


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