Loft Insulation
Loft insulation normally refers to insulation that is required in a cold roofs, that is insulation installed horizontally between and on top of roof or ceiling beams, not insulation installed between and on top of the roof structure and rafters (a warm roof).
In a cold roof the air space above the ceiling joists is ventilated and therefore cold, without insulation between it and the warm house below there is significant risk of the warm moist air from the living spaces rising and then cooling quickly on the cold surfaces of the roof space and condensing. This can introduce moisture on the surfaces of the roof structure which can in turn lead to mould, and decay over long periods.
Introducing one or more layers of insulation between these spaces reduces heat loss and reduces the risks of condensation, preventing warm moist air from entering directly into the loft space.
The first building regulations on home insulation were issued in 1965 and required just 28mm of insulation for a loft, today this is recommended as at least 250 up to 300mm.
[edit] Related articles on Designing Buildings
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- Dew point.
- Diagnosing the causes of dampness (GR 5 revised).
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- Water vapour.
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