Press Information
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| Issued: April 2008 |
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Affordable aesthetics
The primary function of a rainscreen is to protect the inner leaf of a building from ultra violet light and wind driven rain. While meeting these practical requirements has made the rainscreen a popular choice, it is the availability of increasingly stylish finishes that has led it to become one of the most favoured methods of construction. Moreover, recent advances in rainscreen technology have helped to bring down the cost of traditionally premium systems, making them accessible to a range of developments. William Harwood, director, T.I. Dynamic Facades, explains how this has been possible, and what it means for the future of residential construction.
In terms of the rainscreen finish, it is natural materials that are being specified at an unprecedented rate. As well as being environmentally sound, the style that materials such as terracotta and stone offer have greater congruence with current architectural trends.
In response to this increase in demand, façade innovators have used intelligent engineering to develop a new range of terracotta and stone systems. These offer a high quality finish, are easier to install, and most importantly, are affordable for all types of housing.
Intelligent engineering
Although stone is naturally a durable material, to withstand aggressive environmental conditions and provide a viable exterior finish, stone façades have traditionally had to be approximately 40mm thick, in order to deliver the required performance. The consequence of this is that the system is heavy and also takes longer to install, resulting in increased labour costs.
To help make stone more competitive, façade innovators have developed lighter weight systems that 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, slate, 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 overall system cost down. This is because less of the raw material is required per square metre and a lighter weight frame system can be used.
Affordable terracotta
Along with stone, façade manufacturers have brought down the purchase and installation cost of using terracotta for the rainscreen finish.
Historically, twin skin terracotta 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 lighter weight single skin tiles 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.
Easy to install and maintain
One of the main shifts in carrier system technology is the development of vertical hangings. Compared with standard horizontal subframes, vertical systems significantly reduce the number of fixings required, and the fixings used are designed to be virtually invisible. In some cases, when using a terracotta rainscreen for example, no fixings are required at all. As well as reducing the complexity of the installation, this preserves the aesthetics of the exterior envelope.
Large format panels deliver the clean finish demanded by many modern 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.
Engineered with ease of use in mind, some vertical carriers make it impossible for a tile to be fitted incorrectly. This contributes to increasing the speed of installation, because it is much simpler to find the correct place for the tile.
Once installed, a vertical carrier gives greater flexibility in terms of tile replacement and removal. Individual tile access makes the installation of service lines at the end of a site programme straightforward, as the tiles are easily removed and then replaced, until the most appropriate point of entry is identified.
Continuous improvement
As the specification of rainscreens in modern construction continues to rise, façade manufacturers must respond with increasingly innovative and hardwearing systems that also offer an aesthetic finish. The ongoing challenge is to ensure that these technological advances remain affordable to all types of residential development.
