Dear Ben,
When insulating any element (wall, floor or roof) care must be taken not to increase the risks of harmful condensation.
As the insulation performs it job and keeps the heat in your room, the masonry wall behind the insulation will have the potential to be much colder - especially at certain times of the year.
If warm air containing water vapour is allowed to move past the insulation and contact the cold wall then condensation may occur. It is the moisture (condensate) that can cause issues such as mould.
In modern constructions this risk is managed by installing a vapour control on the warm side of the insulation. The purpose of a vapour control layer is to prevent water vapour moving in to the construction where it can cause condensation.
In practical terms the vapour control layer can be achieved in one of two ways.
A sheet of polythene can be installed on to the inside face of the studs before being overlaid with the plasterboard. Joints where sheets meet should be overlapped and sealed to ensure a continuous membrane.
Use of a foil backed plasterboard.
In rare cases ventilation behind the brick work is also required. For example where walls are particularly vulnerable to moisture - such as a wall in a listed building, in poor condition or where severely exposed to driven rain.
For more information, please visit our website
www.celotex.co.uk
Kind regards,
Jamie
Celotex Technical Centre
