Lightweight timber façades have given the material a new life in the building industry by adding strength, insulation properties and ease of handling and installation to the traditional appeal of the timber look.
Timber façades can require less energy to produce than other building products. They require no special tools, while the industrially finished surfaces reduce labour and painting or staining costs. “Installing façades can be done by attaching the material to battens or simply nailing directly to a stud frame using a 40 mm x 2.8 mm hot-dipped galvanized flathead nail. A trained carpenter has all the skills necessary for a well finished job,” John Dalla Via says, sales and business development manger at Carter Holt Harvey (CHH).
A major international brand offered in Australia is Prodex, manufactured by the Spanish timber supplier Prodema. Brad Woods, spokesman for SGI Architectural, which installs Prodex panels in Australia, says Prodex timber facades are suitable for all types of buildings — residential, high-rise blocks, commercial or industrial. “The only qualifications on warranties arise if the building is close to the sea where salt and sand abrasion can be a problem.”
Architects are impressed by the added ability of façades to be used on curved surfaces, with all plywood products offered on the Australian market complying with the Australian/New Zealand standards and are available with Forest Stewardship Council (FSC) certification. “Whether timber is used in domestic, commercial or institutional buildings, its characteristics make it more alive to the public than glass, steel or concrete. Wood gives a softness that people relate to,” Mark O’Dwyer says, director at H2o Architects.
He says the new building for the Royal Melbourne Institute of Technology’s Textile, Clothing and Footwear Department at Brunswick, Melbourne, was one of the first large institutional buildings to use timber facades. “The four-storey building is a warm timber box. It looks like a woven timber tapestry which is appropriate for a training ground for the textile industry. It resembles a child’s matchstick tray and sits in the middle of an old industrial area by a railway line.”
CHH manufactures the Shadowclad range, which offers a textured or grooved appearance applicable for both interior and exterior designs in the commercial and residential markets. The range offers a shiplap weather- groove joint on the long vertical edge of each sheet and choices of proprietary pre-primed, powder-coated finishes for painting, or an un-primed natural surface for staining. These surfaces can be augmented with anodised aluminium flashings for corner and horizontal joints that are profiled to ensure an optimal weather seal.
“Timber facades are being requested even more in building, especially when project owners are seeking a Green Star environmental rating. Timber enhances façades and contributes points for that rating,” Dalla Via says.
An expanding range of plantation timbers, grown specifically for industrial use, is offered by all major Australian suppliers. CHH, for example, use only plantation radiata pine purchased from well managed private and government plantations in NSW, Victoria, South Australia and Queensland. Woods says international timber firms such as Prodema also use plantation timbers.
Shadowclad can be stained or painted, with every colour available in a hardware store from every major producer. However, in a partnership with Taubmans paints, Shadowclad will have a 10-year warranty when prepared and painted to Taubmans’ specifications. Similarly, CHH has partnered with Wood-man’s Cladcoat Semi-transparent Coating System, with staining applications applied to the pre-primed powdercoat finish to extend maintenance levels and improve protection against cracking and peeling.
Prodex has also recently expanded its range of standards colours from five to eight for external panels.
Shadowclad can achieve a R2.0 wall rating with a typical wall installation, including a cavity width, R1.5 insulation batt and 10 mm plasterboard. On the other side of the cavity width is a breathable building wrap onto which the Shadowclad front panel is attached. This combination is not only insulated but also stops moisture problems. The strength in the panel has earnt it an AS/NZS 2269 rating as a structural brace.
Prodex has a composite timber panel constructed of a natural wood veneer that is bonded onto a Bakelite core and has a proprietary coating based on synthetic resins and PVDF to protect against the natural elements and graffiti. Bakelite gives the panel strength and dimensional stability, along with high durability.
“Prodex panels, because they are ventilated, can offer energy savings in both summer and winter, as well as acoustic insulation," Woods says.
Timber facades come in standard industry sizes, with Prodex offering a 1,220 mm x 2,440 mm panel, while Shadowclad comes in three sizes — 1,200 mm x 2,440 mm/2,745 mm/3,050 mm. With both Prodex and Shadowclad, ventilation is important and there needs to be airflow behind the panels to minimise moisture and temperature differentials, with timber or metal battens fitted to the wall and then panels fixed to the battens.
O’Dwyer sees factory made timber façades as an expanding industry and is pleased at the expanding range of Australian plantation timbers, including tallow wood, hoop pine and western red cedar. He also likes the convenience of having the panels made off-site by skilled tradesmen.
“There were too many weather and occupational health and safety issues on a building site, and it is harder to produce precision sizes. The key is to have two layers for exterior usage, with the outer layer providing the aesthetics, and behind it a layer that keeps out the elements.”
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