Impressive life cycle costs, minimal maintenance, ease and speed of installation along the lines of Modern Methods of Construction, and contemporary aesthetics are just a few of the reasons why more and more specifiers are using rainscreen cladding systems.
Ian Barclay, general manager of technical support services at Marley Eternit, which is seeing its range of fibre cement rainscreen cladding panels used on an increasing number of refurbishment projects, reviews the reasons why.
Far-sighted specifiers and building owners appreciate that while the actual cladding material can be more expensive to buy in the first instance, than render for example, it outperforms other systems over a whole life period.
Supplied already weather and fire resistant, it is then quick and easy to install (it can be pre-fabricated off site) and therefore minimises build costs, and requires minimal maintenance so therefore minimises on-going costs.
In addition, the new Part L regulations mean that many buildings require refurbishment purely or partly because they do not perform adequately when it comes to thermal insulation.
Improvements to the thermal insulation of domestic properties is relatively easy – loft insulation, cavity walls and replacement double glazing – but in commercial buildings where internal space is usually at a premium, external insulation incorporating rainscreen cladding could be the answer since it only adds 100mm to the footprint of a building.
From ugly ducking into swan
Insulation was one of the reasons why William Peden architects specified rainscreen cladding for the refurbishment of Bathgate police station.
WPa’s brief was to replace the 1960s asbestos and glass panels within an aluminium patent glazing system with a new frontage that met current building standards - the existing façade was too hot in the summer and too cold in the winter.
Lothian and Borders Police required the station to remain operational throughout the 10-month build and WPa identified sectional timber frame construction as a solution to the requirement for speedy erection on site and minimal disruption to users. A temporary wind and waterproof inner screen was erected before the existing façade was removed.
The new façade comprises a pre-fabricated 150mm timber frame containing insulation, vapour barrier and breather membrane. Rainscreen cladding panels, secret fixed onto a hanging rail system of battens, were then fixed on site.
William Peden said: “The existing building, although otherwise in good condition, was seriously compromised by the frontage both in appearance and performance. Rainscreen cladding was chosen as it allowed the introduction of colour without resorting to applied surface finishes.”
Come hell or high water
What was the redundant, dark green Rookwood primary school in Eastleigh, Hampshire, is now the bright headquarters of Hampshire County Council’s Music Service … but it took fire and floods to get it that way.
Although the rainscreen cladding now plays a major part in the way the building looks, the original project – to convert the 1980s school to offices for the music service which was originally housed on a site flooded out a few years before – did not propose re-cladding.
However, before work could start, a significant fire occurred, necessitating the need for substantial repair works as well as the alterations. What little cladding had not been damaged in the fire was defective anyway so the decision was made to replace it in its entirety.
Geoff Curran, a property services manager for Hampshire County Council, said: “The rainscreen panels provided a durable external cladding and were certainly an improvement on the original stained plywood, making the building look more 21st Century.”
Realising destiny
Nord Architecture’s client – Destiny Church in Glasgow – had thought that the 1970s concrete and brick extension to their 19th century, Grade II listed parish church would be refurbished with render and paint as a simple solution to a tight £50,000 budget.
The refurbishment had become necessary because although the building was sound structurally, cosmetically it had deteriorated and required an upgrade. The brief was to improve the appearance of the extension that was an eyesore in relation to the church.
It was also used as much for the local community as it was for congregation and Nord’s design had to articulate its public function. Creating a visual impact within the environment would draw attention to its activities within the community.
The rainscreen cladding panels comprehensively wrap the exterior, blocking off all windows to create a black-box environment for another community use - television production.
Some 100m² of the panels were secretly fixed over the existing brick elevations onto a treated softwood frame using structural adhesives to avoid having the appearance of screws and caps.
Robin Lee of Nord said: “As all the panels were pre-cut, the installation was extremely quick. After the framing was in place, the cladding was completed in just seven days. Selecting a panel material was the most important decision but it has been hugely successful.”
Conserving an industrial feel
HEAT Architects specified rainscreen cladding panels for the £1.8million refurbishment and extension of two 1950s buildings at the heart of the urban regeneration of the historic and Conservation Area of St John’s Square in Clerkenwell, central London
Sub-contractor LSC installed the cladding in a horizontal shiplap format over a lightweight timber frame on the new facades and to the new-build penthouse with its steel superstructure and lightweight timber infill panels.
Associate Elizabeth Crawford said: “The rainscreen cladding was specified for its clean lines and contemporary aesthetic. It should maintain well with little maintenance, which makes it ideal, as there is limited access to the facades of the building without the use of a high-reach vehicle.”