Andy Noble of CD (UK), the distributor of Corian in the UK and Ireland, investigates a relatively new solution for ventilated facades which offers fascinating possibilities.
Meeting a set of challenging demands for the building envelope, from aesthetics to thermal efficiency, and straightforward installation to enduring performance, solid-surface rainscreen cladding has been seen on a number of high-profile and award-winning projects recently. Naturally, safety is also a vital issue – and an area in which expertise, testing and multiple, relevant certification makes such products a reliable option.
A rainscreen facade must perform several key functions. As well as protecting the structure from the elements it can help to manage interior temperature and comfort by circulating air through a cavity, and reflecting or absorbing solar gains. A ventilated facade also allows a building to breathe, and helps to minimise and drain away moisture that can be a problem in any season. Also, temperature and pressure differentials can be managed in a way that maintains thermal stability and reduces the need for mechanical heating or cooling systems.
A genuinely high-performing material will perform in all climates and regions, be resistant to chemicals in pollution, graffiti or other damage, while also being easy to clean and even discreetly repairable. In addition a homogenous and non-porous surface means stains cannot penetrate as well as the material being through-coloured.
Fire resistance is obviously also essential. For example, Corian has passed the demanding EN 13501-1 norm (including the SBI test) for panel dimensions typical to facade applications. Sustainability may also be a key consideration. Solid surface is renewable and re-useable, in most cases, and industry leaders such as DuPont have achieved zero waste to landfill during manufacture.
Visually, a structure’s skin must be sympathetic not only to the architectural vision, but also to its surroundings. Solid surface can gives a dynamic first impression, or enable a building to blend subtly within its setting. Few materials offer the creative freedom, in this regard, that a premium quality solid surface does. Via CNC technology and through a network of highly skilled fabricators, it is possible to add engraved patterns or raised 3D effects, while thermo- forming and seamless joining can add curves or a distinctive sculptural quality to a design.
Specifying the right surface allows for inventive design and application, demonstrating a material’s ability to provide inspiring versatility. This also means it’s compatible with either standard or bespoke installation systems including the option to include back lighting or projection.
Extra-large panels (for example, Corian comes in sheets of up to 1,500 mm width) can also facilitate both the design and fitting process. Current mounting systems allow panel sizes of up to five metres in height, enabled by a substructure which can accommodate the movement due to thermal expansion. The weight capability of the mounting system and the necessary expansion gaps must be taken into account. Since colours run through the entire thickness of a high quality solid surface, the edges of panels are in the same colour as the rest of the sheet. Thus, revealed or overlap joints will not show any dark gaps between panels, and can be as discreet as desired.
The method usually employed to fit solid surface cladding is a mechanical fixing system based on an aluminium grid consisting of vertical profiles in a ‘T’ or ‘L’ shape, mounted on aluminium squares connected to the substrate. The panels are hung on the horizontal profile ‘C’ shape by the brackets (or clamps) with reverse ‘C’ shape, that are attached to the back of the panel with a specific undercut anchor.
There are now multiple high-profile installations internationally featuring exterior cladding in Corian. The latest UK example is the £10m NGS Macmillan Unit at the Chesterfield Royal by The Manser Practice, which will be featured in detail in the Design for Health & Social Care Supplement, to be published with the March issue of ADF.
Andy Noble is sales director for CD (UK)