March 2008
Rainscreen Becomes A Fashion Statement
Speed of build originally made rainscreens a contemporary construction choice and the systems continue to rise in popularity as increasingly stylish and natural finishes are launched to market. Although these rainscreens are historically the preserve of premium developments, technology innovations are helping to bring the cost down and make these high quality exteriors accessible to all.
While the primary function of a rainscreen is to protect the inner leaf of a building from wind driven rain and ultra violet light, trends in modern architecture have made the systems as fashionable as they are functional. As an exterior finish, rainscreens provide complete design versatility and enable some of the most striking and unusual designs to become a reality.
There are many different types of façade systems on the market, offering a range of colours, textures, shapes and sizes. Although product innovation and local environmental factors have a strong influence on the popularity of these different systems, emerging patterns suggest natural materials such as stone and terracotta are set to be the facings of choice – with increased affordability acting as the catalyst.
Stone – affordable and light
To withstand aggressive environmental conditions and deliver the required performance, natural façades have traditionally been of a thickness that has made them heavy and difficult to handle on–site. The consequence of this is that the system generally takes longer to install, resulting in increased labour costs.
Directly addressing this challenge, façade innovators have developed lighter weight systems which are durable and easier to install than conventional constructions. Where stone is concerned, this has been achieved by creating a facing that is reinforced with a high strength fibre, aluminium or aluminium honeycomb backing. Stone facings are manufactured 6mm to 15mm thick and bonded to one of the backing systems, with the type of backing determined by the specification requirements of a project.
Sandstone, limestone, granite, basalt and marble can all be manufactured in this way to achieve a durable, high performance finish, without the need for a stonemason. While this offers an on-site cost saving because it substantially reduces site programmes, it also brings the system cost down because less of the raw material is required per square metre.
Terracotta – the next generation
At the same time as advances in stone facing technology, a new generation of terracotta systems has emerged. Compared with conventional terracotta systems, these new systems remove the need to use a twin skin design. An innovative manufacturing process uses a porcelain base, baked at a high temperature, to give the single skin tile increased strength and durability.
The precision calculated carrier systems of these modern terracotta systems offer complete design versatility as well as fast installation. To accommodate the full range of design requirements, they are available in module sizes ranging from small, typically 150mm x 800mm, to very large at 300mm x 1,200mm. Large format panels deliver the clean finish demanded by many premium developments, and remain easy to install owing to the sophisticated carrier system and minimal weight of the tile. At the same time, smaller tiles provide a cost effective solution for breaking up the monotony of a lower end finish, such as render. This is because the carrier system will easily integrate with the primary frame of most alternative exterior finishes.
Emerging trends
Natural façade systems provide a very high quality look and feel for a building exterior. Commonly used for new build commercial developments there has been a recent shift towards greater use in residential apartments. With advances in façade technology having made natural systems more affordable, durable and easier to install, a sharp rise in the number of residential projects adopting these rainscreens as the preferred finish is anticipated.
Terracotta is already a popular choice in urban areas and this is expected to continue. It is the advancements in stone facing technology that are likely to make the most significant impact on the use of rainscreens, particularly in rural areas. Planning permission is often granted on the basis that the new development will be in keeping with the existing environment. For rural Scotland, a stone rainscreen would previously have been a cost prohibitive construction, but is now a viable option that will deliver a high quality external finish as well as strong commercial benefits.