Summary
• Weinmann lines can manufacture increasingly finished articles.
• Its focus is closed timber panels, but its machines handle semi-open too.
• Weinmann also makes production line assembly tables and stacking systems.
• The company provides engineers to train and oversee site workers.

To see the future of timber building, head for St Johann-Lonsingen. This tiny village in Germany’s Swabian Alps is home to a business making house fabrication technology which 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 fitted, but even an initial render – and one makes panels up to 24×3.2m. These, in turn, speed up construction, delivering weather- tight house shells in as little as three days. At the same time, their insulation and airtightness levels make achieving environmental standards like Passivhaus a shoe-in.

Almost as incongruous as its location is the fact that Weinmann began in the 1980s making machines for wooden pallets. In a sign of things to come, however, it didn’t stay making them the conventional way for long. The company’s founding partners were fellow Reutlingen mechanical engineering graduates Karl Weinmann, Alfred Schlegel and Hansbert Ott and they were soon applying their expertise to automating production. The result was an advanced CNC nailing system and the seeds of the future Weinmann operation.

The switch to timber building technology was, to a degree, forced on the company by new packaging rules outlawing the pallets for which its system was designed. But project team manager Jörg Gross said it was also 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 – just on a different scale,” he said. “So, following discussions with timber building specialist Schwörer Haus KG, the company began to develop technology for the market.”

From the outset Weinmann’s focus was the closed timber frame panel most commonly used by German builders, as opposed to open or semi-closed panels still preferred in the UK. The core of these is a softwood frame generally comprising 180x80mm stud, although some house manufacturers now produce panels up to 400mm thick to accommodate extra insulation using solid timber, glulam or I-joists.

Internally the finished wall panel coming off a Weinmann line will have a plasterboard skin. The next layer will be OSB or chipboard and a breather membrane, while the frame void will be packed with insulation.

“This could be glass or rock wool, but increasingly fabricators are favouring natural products, such as sheep’s wool, hemp or wood fibre board,” said Mr Gross.

External finish

Externally the frame has OSB or cement particleboard attached, then another layer of insulation, such as EPS, or wood fibre, followed by some form of mesh or membrane depending on the final exterior finish required.

“In Germany the preference is render or wood cladding, or both,” said Mr Gross. “Although in the north, like the UK, people prefer brick, so house suppliers add an outer brick skin.”

A complete Weinmann line can tackle virtually all aspects of closed panel production semi- or totally automatically. To paraphrase its brochure; beams go in one end, finished products emerge the other.

The business end of the system is the multi-function bridge. This is effectively the successor to that first nailing system, but slightly more advanced, comprising several machines 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 parallel fastening tools, plus sawing, milling, drilling and labelling head options. Still more advanced, the WMS 150 places and fixes sheathing and battens onto a frame beam or rafter automatically.

A fully-integrated plant will also include a computer-controlled framing station and other parts of the modular Weinmann mix can comprise a WBZ beam processing station or WBS high speed linear saw. The most advanced version of the former comprises a “fully flexible” sawing, drilling and routing unit that marks and labels components, while the linear saw cuts, marks and labels “the entire scope of parts for trusses and wall panel components”. Like the multi-function bridges, these come with a range of CAD/CAM-interfacing control and monitoring software options.

Weinmann also makes production line assembly tables and panel turning and stacking systems. More recently it has developed machines to process newer engineered wood products, including I-beams, SIPs and solid wood panels and beams, such as glulam and cross-laminated timber.

For the latter it has designed process centres capable of sawing, drilling and milling material up to 350mm thick. Mr Gross pointed out one of these giants on a tour of the 7,500m² factory. It weighed 10 tonnes but, despite its size – and it included a 960mm circular saw, 5-axis machine head and 18-tool automatic tool changer – the sound-proofed cabin meant that it emitted no more than a low hum as it travelled along its assembly table slicing into a glulam beam.

Helping drive technical developments at Weinmann is the fact that, since 1998 it has been part of the giant Homag wood-processing machinery group.

“We share technical expertise across the group and Homag’s input on control software has been particularly valuable,” said Mr Gross.

Joining the global Homag operation also took Weinmann fully onto the international stage. In fact exports today account for 85% of turnover and its individual machines and complete turnkey production lines can be found as far afield as North and South America, Japan, Australia and South-east Asia, with particularly strong prospects now seen in Russia, Brazil, China and India.

A challenge in some of these markets is that they’re unfamiliar not just with automated timber-frame panel production, but timber building itself. So Weinmann provides customers not only with machine operator training, plus an online diagnostics service for technical problems, but back-up in house construction too.

Training and back-up

“Our technology is only as good as the quality and performance of the customer’s finished buildings,” said Hansbert Ott. “So we provide engineers to oversee and train site workers. This can be a long-term commitment, for instance a new Chinese customer wants two engineers for 12 months.”

Thanks to UK house fabricators’ preference for open or semi-open panels, a large proportion of Weinmann’s sales here have been of individual machines or part lines. But the company believes more companies will follow the example of Space4, CCG and Scotframe and go for full, integrated production systems.

“UK timber frame companies are still cautious about taking responsibility for complete closed panels, in case they have to undertake 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.”

Because of the modularity of the Weinmann production system, said Mr Gross, it’s also straightforward for manufacturers to start with a partial line and build up to a complete closed panel facility. What might help more companies make the transition is the new compact WEK 120, a combined framing station and multi-function bridge for wall and gable production.

“This is suitable for semi-closed panels, but can also be integrated into a closed panel system as manufacturers develop,” said Mr Gross.

More finished, more efficient

Looking ahead, Weinmann predicts its technology 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 170 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; buildings with smaller carbon footprints, that need less energy to heat and cool,” said Mr Ott. “Timber has the inherent advantage of being renewable and a natural carbon store and prefabrication is clearly the best way to achieve the insulation required.”

In short, it looks like the future of timber building will be in St Johann-Lonsingen for some time to come.