to Ventilation Index
Stale air can be caused by cooking smells, smoking,
odours remaining in the bathroom, a general lack
of ventilation around the house as well as a damp
problems cause an avoidable level of discomfort
as well as the risk of respiratory illness and general
Problems occur when steam from the kitchen or bathroom
finds relatively cooler surfaces around the house
and condenses. Attempts to conserve heat by sealing
windows - and therefore reducing natural ventilation
- makes this problem even worse.
can cause considerable problems, from peeling wallpaper
and mould growth to severe structural damage such
as wood rot and damp when the relative humidity
regularly exceeds 70%.
For over 50% of the time the 'dry' South East
of England, and for 70~80%
of the time across large areas of Western Britain,
the humidity level is greater than
Severe condensation damage affects over 4.5 million
British homes and has been estimated to cost over
£500 million per annum - the direct result
of inadequate ventilation.
And it's not just a feature of poor quality housing.
The best-insulated and draught-sealed properties
are equally at risk - perhaps more so - as water
vapour produced in the kitchen and bathroom finds
the relatively cooler surfaces in halls and bedrooms
where it condenses.
Artificially low ventilation rates due to sealing
of windows to conserve heat and the absence of
flues in many modern buildings exacerbate the
problem. That's why the Building Regulations Document
F amended by the Building Regulations (Amendment)
1994, the Approved Document F requires that an
adequate means of ventilation should be provided
and includes guidance on kitchens, utility rooms,
bathrooms and sanitary accommodation.