The modern concept of rainscreen overcladding was developed in Scandinavia during the 1940's and came into widespread use in Europe and Canada in the 1970's.
Lightweight rainscreens were developed in the UK in the 1980's with the majority of the earlier projects being located in the harsh climatic conditions of Scotland. Rainscreen is not a new concept and many years of experience have been gained in the development of the relatively easily installed lightweight systems currently available.
The growth of the modern rainscreen system came about in the 1980's as a result of buildings erected in the 1960's, reliant upon the primary seals (either gaskets or wet seals), failing because of breakdown caused by weathering. This resulted in sprawling concrete and mosaic. The easiest solution was to contain the problem by overcladding in a lightweight metal rainscreen cladding. Further growth was accelerated by ever increasing demand for higher thermal efficiency.
Rainscreen is a cladding system consisting of an outer weather-resistant skin fixed to a primary structure, either new or existing, using fully adjustable brackets. This allows insulation (with integral or separate breather membrane) to be pinned back to the primary structure, leaving a ventilated cavity 25mm minimum to comply with CWCT requirements and 38mm minimum to comply with NHBC standards. This ventilated cavity must be present in all systems behind the primary aesthetic weathering façade.
The fully drained and ventilated system allows for any ingress from driven rain to be channeled and drained, allowing any residual moisture to be taken care of by a natural thermocycling process.
New primary construction methods using metal stud built-up walls and structural insulated panel systems (SIPS) are fast becoming the preferred method of construction as they can provide increased speed of erection with greater thermal efficiency. Providing a dry envelope much earlier in the construction program.
All ventilated rainscreen systems provide an element of pressure equalisation. For complete pressure equalisation, whereby the air pressure differential across the total façade is held in equilibrium resulting in the total elimination of pressure induced water penetration, the following design criteria must be applied:
CWCT performance criteria requires the ventilated area to be a specific proportion of the volume calculated for each zone. Differing methods of ventilation, panel sizes, cladding zones all play a part in the equation requiring specific calculations on a project by project basis.
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Having little or no aesthetic values primary structures need the vast range of attractive and finishes offered by the Sotech range of cladding solutions, from traditional to contemporary, to bring a project to life.
Sotech is at the forefront of rainscreen design, having developed a comprehensive suite of systems. Able to support natural materials such as copper, zinc, stainless steel and aluminium, as well as aluminium composite material and high pressure laminates, our systems provide architects and specifiers an almost limitless choice, enabling their individual design intent to fully realised.