dampness and condensation
health & relative humidity
The relative humidity of the air in the majority of homes tends to between 50-70%. The optimum level of Relative Humidity of between 50-55% with levels between 30 and 70% generally fine.
the most common cause of damp is through disrepair
Dampness can be caused by water entering your home from the outside. This will be caused by:
1 Leaking pipes, wastes or overflows
2 Rain seeping through the roof where a tile or slate is missing, spilling from a blocked gutter, penetrating around window frames or leaking through a cracked pipe
3 Rising damp due to a defective damp course or where there isn't a damp course or where the outside ground level is higher than the damp course.
This form of damp is different from condensation because the cause of the damp tends to leave a tidemark and it will be much wetter nearer the source of the problem.
Repairing problems caused by damp will primarily depend on the correct diagnosis of the cause of the damp and will require a survey of the building or dwelling.
If your home was built in the last 40 years then your damp problem is 90% most likely to be caused by condensation.
Condensation is caused by warm moist air mainly from drying clothes indoors, cooking, bathing and breathing.
The most obvious sign of condensation is water streaming down the inside of windows or walls but can also form in corners of ceilings and walls, under bay windows, behind furniture or on clothes and bedding.
Improving heating or insulation will help eliminate condensation by raising the internal temperature of the dwelling or building and therefore lowering the relative humidity. However removing the moist air through improved ventilation is probably the most effective solution for newer dwellings.
no extractor fans in bathrooms or kitchens
We recommend the installation of extractor fans in the bathroom and kitchen.
A bathroom extractor fan with a humidity control means it comes on at a low speed when high levels of moist air are detected and can be installed for around £200-300.
A bathroom extractor fan with heat recovery will cost around £200 more to install but will recover around 80% of the heat lost, saving you around £25 -£50 a year. It will also lower the relative humidity levels by keeping temperatures higher.
Both types of fans will cost around £7 a year to run.
extractor fans installed in bathrooms and kitchens
We recommend the installation of positive input ventilation. This ventilation unit sits in the roof space and blows filtered air from the roof space into the dwelling removing stale air through windows and doors. It should lower relative humidity levels by around 10% and works best with trickle vents or humidity control fans. The unit costs around £400 to install and under £7 a year to run.