External wall insulation

External Wall Insulation (EWI) systems involve the installation of an insulating layer to the external fabric of an existing, or new building, the system is usually finished with a render coat, brick slips or clad with timber boards or tiles.

Unless an existing building is already rendered or clad the installation of EWI can dramatically alter and improve the appearance of the external facade.

An EWI system makes use of the thermal mass of the wall which in turn helps to provide less peaks and troughs in the internal environment. This is particularly beneficial in buildings such as hospitals and retirement homes which are often continuously heated and can allow the heating system to be turned down overnight as the energy absorbed by the wall during the day is released back into the internal environment overnight.

When deciding which EWI system is most appropriate for the circumstances there are several issues that need to be considered. However, the most important issues are the level of thermal performance to be achieved, the insulation type and which finish is the most suitable.

A wide variety of insulation types can be used in EWI systems. Knauf Insulation Rocksilk EWI Slabs are high impact strength rock mineral wool slabs with a water repellent additive specially developed for external wall insulation systems. Their manufacture has a very low impact on the environment.

Rock mineral wool products are non - combustible which negates the need to install fire barriers and and gives the specifier a high level of assurance regarding the fire safety of the design.

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