To see the future of timber building head for St.Johann-Lonsingen. The tny village in Germany's Swabain Alps is home to a business making house fabrication technology which, it it probably no exaggeration to say, is helping change the face of construction.
WEINMANN's computer-controlled, automated machinery is not only productive - its biggest installation to date produces components for 2,000 houses a year on a single shift - it can also manufacture increasingly finished articles. Some operators, for instance, supply exterior wall panels to site with not just doors, windows and service ducts fittes, but even an initial render - and one makes panels up to 24 x 3.2 m. Such components, in turn, speed up construction, delivering weathertight house shells in as little as three days. Their insulation and airtightness levels also make achieving environment standards like Passivhaus a shoe-in.
Almost as incongruous as its location is the fact that WEINMANN began in the 1980s making machines for pallets. It didn't stay making machines for pallets. It didn't stay making them the conventional way for long, however. The company's founding partners, fellow Reutlingen mechanical engineering graduates Karl Weinmann, Alfred Schlegel and Hansbert Ott, were soon applying their expertise to automating production. The result was an advanced CNC nailing system and the seeds of the future WEINMANN operation.
According to project team manager Jörg Gross, the move from here to timber building technology was a natural progression.
"It's a simplification, but the essential elements of the pallet and the frame of a timber building panel are quite similar - jsut on a different scale, " he said.
From the outset WEINMANN's focus was the closed timber frame panels most commonly used by German builders, as opposed to the open or semi-closed panels preferred in the UK. The core of these is a a softwood frame generally comprising a 180 x 80 mm stud, although some house manufacturers now produces panels up to 400 mm thick to accommodate extra insulation using solid timber, gluelam or I-joists.
Internally the finished wall panel coming off a WEINMANN line has a plasterboard skin. The next layer is OSB or chipboard and generally a breather membrane, while the frame void is packed with an insulation of the manufacturer's choice.
"This could be glass or rock wool, but increasingly our customers favour natural products, such as sheep's wool, hemp or woodfibre board," said Mr. Gross.
Externally the frame has OSB or cement particleboard attached, then another layer of insulation, such as EPS, or woodfibre, followed by some form of mesh or membrane depending on the final exterior finish.
"In Germany the preference is render or wood cladding, or both," said Mr Gross. "Although in the north, like the UK, people like brick, so house suppliers add an outer slip."
A complete WEINMANN linke can tackle virtually all aspects of closed panel production semi - or totally automatically. The business end of the system is a multi-function bridge. This is the sucessor to that first nailing system, now comprising several machines and multiple functions in one. Even the entry level WMS 100, which is equipped with fastening and sawing or milling heads, can automatically nail sheet materials to the frame and mill service sockets and window and door cut-outs. A step up, the WMS 110 is billed as the "fastest multi-function bridge in the world". This comprises two paralles fastening tools, plus sawing, milling, drilling and labelling jead options. Still more advanced, the WMS 150 places and fixes sheating and battens onto a frame beam or rafter automatically.
A fully-integrated plant also includes a computer-controlled framing station, and other parts of the modular mix can include beam processing stations and high-speed linear saws. The most advanced version of the former comprises a "fully flexible" sawing, drilling and routing unit that also marks and labels components. Like the multi-function bridges, these other machines vome with a range of CAD/CAM-interfacing control and monitoring software options.
WEINMANN makes production line assembly tables and panel turning and stacking systems too and it has also developed machines to process newer engineered wood products. These include I-beams, SIPs and solid wood panels and beams, such as gluelam and vross-laminated timber. For the latter it has designed process centres capable of sawing, drilling and milling material up to 350 mm thick.
Helping drive technical developments at WEINMANN is the fact that, since 1998 it has been part of the giant HOMAG woo-processing machinery group. Joining the global HOMAG operation also took WEINMANN fully onto the international stage. In fact exports today account for 85% of turnover. A challenge in some of its newer markets, including China, is that they're unfamiliar not just with automated timber frame panel production, but modern timber building per se. So WEINMANN provides not only machine operator training, but back-up in house construction too.
"Our technology is only as goog as the quality and performance of the customer's finished buildings," said Hansbert Ott. " So we also send engineers to oversee and train site workers."
Thanks to UK house fabricator's preference for open or semi-open panels, a large proportion of WEINMANN's sales here have been of individual machines or part lines. But it believes more companies will follow the example of Space4, CCG and Scotframe and opt for full, integrated production systems.
"UK companies are still cautious about taking responsibiltiy for complete closed panels, in case they have to understand remedial work on site," said Mr. Ott. "But there's increasing appreciation of the added value and quick-build benefits of closed frame and the fact that, as they're finished with much more precision in a controlled environment, they're less likely to have quality issues than site-finished."
Looking ahead, WEINMANN predicts its technoloy will become still more efficient, automated, use more advanced software and produce an ever more finished product. An example of things to come is the WMS 280 Plaster multi-function bridge. Previously, where fabricators wanted to apply an initial render in the factory, it had to be done manually. The WMS 170 incorporates an application system so it's done automatically - and it can also apply adhesive for bonding further layers of board or insulation.
Mr. Ott's other prediction is that the construction market worldwide will continue to head WEINMANN's way, with offsite manufacture and timber frame inevitably becoming more popular.
"Rising fuel prices and growing environmental awareness mean the main market driver is towards sustainable construction," said Mr. Ott. "Timber has the inherent advantage in this market of being renewable and a natural carbon store, and prefabricating timber buildings is clearly the best way to achieve the energy efficiency needed."
In short, it looks like the future of timber building will be in St.Johann-Lonsingen for some timbe to come.
Source: Timber & Sustainable Building, Issue: Summer 2011