External Facade Thermal Insulation

There are a wide variety of proprietary rainscreen cladding systems available most of which have the insulation installed on the external face of a masonry wall, this helps to keep internal temparatures stable by storing heat in the winter and reducing solar gains in the summer. Rainscreen cladding systems are also lightweight when compared to brick and masonry solutions and they can provide the designer with a wide range of aesthetic options.

Rainscreen cladding systems are designed to keep both the structural frame and the thermal insulation dry, due to the rainscreen cladding itself but also due to the airspace between the cladding and the insulation.

Drained and ventilated rainscreen systems work by allowing air to enter at the base of the system and escape at the top of the system, the ventilated cavity allows water penetrating the panel joints to be partly removed by the ‘stack effect’ and partly removed by running down the rear face of the panels and out of the base of the system.

For external wall constructions that include cavities, such as rainscreen cladding systems, cavity fire barriers are recommended at the junctions between the wall and every compartment floor or wall or other wall or door assembly that forms a fire-resisting barrier.

Fire barriers should be made from non-combustible material, be at least 100mm high and penetrate the full depth of the insulation and form a continuous barrier through the insulation layer.

Rainscreen cladding systems comprise outer cladding panels that are bolted to a supporting framework of rails, which are supported by brackets fixed through a thermal break pad back to the building frame. A layer of insulation is fixed independently against the building substructure using proprietary insulation fasteners.

Facade Slab is recommended for this application, as it is lightweight but rigid enough to resist the compression forces generated when installing the insulation slabs on the masonry substrate.

Facade Slab is a Glass mineral wool slab containing a water repellent additive, specially developed for rainscreen cladding applications. Its manufacture has a very low impact on the environment.

Download the Cladded walls application PDF