When it comes to choosing the right rainscreen cladding system, it's important to consider these seven different factors to ensure a successful installation.
Although, first of all, it would be a good idea to establish 'What is rainscreen cladding and how does it work?' if you don't already know.
In a nutshell:
- The weather conditions in different locations can affect material and coating specifications.
- U-value should be considered, especially with Passivhaus projects.
- For high-rise buildings, rainscreen cladding systems must use materials that are minimum A2 fire-rated.
- Sound absorption is important, particularly in built-up urban areas.
- The design should allow airflow and water drainage.
- Rainscreen cladding comes in a range of panel designs and colours.
Project location
Location can play a vital role in rainscreen cladding specification due to differing weather conditions. A rainscreen cladding system for a building in the Scottish Highlands, for example, may require stronger fixings, smaller panels and stronger brackets due to the increased wind loads. Whereas a development in a coastal location would require marine grade coating to protect the system from the corrosive effects of salt spray.
CWCT testing
The Centre for Window and Cladding Technology (CWCT) provides resources which help architects to make informed decisions during the specification process. Resources include technical guidance, testing and certification, research and development, and collaborative platforms which helps ensure compliance with industry standards and regulations.
Thermal/heat transfer (U-value)
The cladding alone contributes very little to a building’s thermal efficiency which is why an insulation layer is fitted. Specifying the correct system build-up and materials should be considered in order to meet the required U-values on a project, particularly for Passivhaus developments which are designed to provide optimum comfort for occupants with little energy usage.
Building regulations and fire ratings
The Building Regulations stipulate that rainscreen cladding systems on high-rise buildings must use materials with a minimum A2 fire rating.
Aluminium, terracotta and ceramics all possess minimum A2 fire ratings which makes them compliant with The Building Regulations, however, architects must ensure that the insulation material and cavity barriers are also A1 non-combustible.
Sound absorption
The material used in the insulation layer of the cladding can also attribute to sound absorption. The fibre structure of mineral wool absorbs sound which reduces decibel ratings, making it ideal for residential buildings beside main roads and railways.
Air and moisture management
The design of the rainscreen cladding should allow for proper air flow behind the cladding to prevent moisture build up and promote drying. The system uses an open cavity which encourages ventilation and allows the building to ‘breathe’. The size of the air gap is dependent on the type of rainscreen panels used, although the standard size is between 25mm and 50mm.
Aesthetic appeal
Rainscreen cladding comes in a range of panel systems (laser cut, perforated, solid) and colour options to assist a building’s visual appeal. The desired look for the rainscreen cladding comes down to the choice of coating; powder-coating has over 2,000 colour options whereas anodising has a smaller palette but provides a richer, metallic finish and more robust protection.