Press Information
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| Issued: January 2008 |
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Rainscreen cladding technology: Improving quality and increasing affordability
While the primary function of a rainscreen is to protect the inner leaf of a building from wind driven rain and ultra violet light, the development of increasingly stylish and natural finishes is making this modern construction method as popular for its design as it is for practicality. Although these finishes are historically the preserve of high-end developments, advances in rainscreen cladding technology are helping to bring the system cost down and make these premium exterior finishes more accessible.
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 relative popularity of rainscreen constructions, emerging patterns suggest natural materials such as stone and terracotta are set to be the facings of choice. Moreover, as technology makes the natural finishes increasingly affordable, there is expected to be a sharp rise in the specification of these systems.
Lightweight stone facings
Despite a lot of general interest in stone finishes, there has been a noticeable resistance to using these facings. The main reason for this lies in the thickness of the material, which, to deliver the required load bearing and environmental performance characteristics, traditionally had to be at least 40mm. As a consequence, the systems were bulky and difficult to handle on-site, resulting in a longer installation process and increased labour costs.
To help make natural finishes such as stone more competitive, 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, slate 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 overall system cost down because less of the raw material is required per square metre.
Modern terracotta systems
At the same time as advances in stone facing technology, new terracotta systems are emerging which make the system a natural choice for all types of development. Historically, twin skin tiles have been necessary to deliver the required impact performance. However, new systems launched to market are removing the need to use a twin skin design because technological advances have made the lighter weight single skin tile a viable option.
Increased strength and durability is achieved through an innovative manufacturing process. A porcelain base baked at a high temperature significantly reduces the water absorbency of the system, making it more resistant to the freeze/thaw phenomenon that causes some silicon sprayed alternatives to fail.
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 400mm, 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 vertical carrier system will easily integrate with the primary frame of most alternative exterior finishes.
The continual innovation being seen with natural rainscreen finishes is likely to give rise to increased demand for the construction type. Moreover, façade manufacturers are pioneering crystallised urban glass systems, which are expected to prove as popular as natural products, owing to the high quality yet cost effective finish that these innovative designs deliver.
