Cross-laminated timber in Portuguese

On the initiative of German entrepreneur Dr. Gerd Jakob, who had emigrated to Portugal, the idea of the first integrated cross-laminated timber concept on Portuguese soil was born in 2020. One year later, Arolla, a company which accompanies the raw material wood from its origin in the forest all the way to the turnkey building, was established. This is precisely how Arolla wants to set itself apart from the competition. “We are more than just a manufacturer of cross-laminated timber and a product supplier. At Arolla, we want to offer our customers the complete package from a single source: from meticulous planning done by our own architects to our state-of-the-art production as well as assembly on the construction site,” founder and owner Dr. Jakob says, explaining the underlying corporate philosophy.

To put this philosophy into practice, Arolla employs around 50 people from all trades and built a modern cross-laminated timber production facility, which meets high technical standards, in an existing 11,000 m²-big factory hall in the port city of Setúbal, around 50 km south of the Portuguese capital Lisbon. There, the company produces up to 50,000 m³ of cross-laminated timber elements a year, which are used for the construction of turnkey buildings and residential complexes in Portugal and beyond.

Sophisticated technology

Turnkey is also a suitable keyword for describing Slovene machine manufacturer Ledinek. The scope of delivery of the glued timber experts includes everything, from the tilt table de-stacking of the raw wood at the factory entrance to the joining of the produced CLT elements. In fact, the company was responsible for almost all of the main machines used for the entire production process. Ledinek only relied on long-standing partner companies for the adhesive application technology and the vacuum lifters as well as for the finger-jointing machine, which, as experience has shown, is subject to less stress in the production of system-format panels.

Use of pine wood to be increased

With regard to the raw material, Arolla uses local pine logs as well as spruce logs which are imported from Central Europe. Additionally, more weather-resistant larch wood is used primarily for exterior façade elements. “We only buy strength-class sorted lumber, either from small local sawmills or from Central European partner companies. Our aim is to create more added value here in the region and to constantly increase the percentage of Portuguese pine logs,” Richard Santner, who accompanied the Arolla project from the beginning, says, giving up to 80% of pine wood as the target.

Well-known and established companies are also trusted for the remaining components of the various buildings. For example, Arolla maintains a close partnership with Austrian window manufacturer Gaulhofer, which is based in Übelbach near Graz, and runs joint pilot and research projects.

A well-rounded complete package

First, a side loader forklift transports the purchased raw wood to the tilt table de-stacking system, where the laminations are singulated and their moisture is measured as they pass through. Next, the laminations enter the Multiplan planer, which calibrates the wood on all four sides at a feed speed of up to 200 m/min. Parallel to the planer, there is the Minizink, a horizontal finger-jointing line from Ledinek. “We deliberately designed the Minizink as a separate isolated solution. However, thanks to our 1,200 mm-wide standard elements, the effort required for and the use of this machine are kept within limits,” Santner explains.

In CLT production, Arolla uses mainly solid single-layer panels. To produce them, the freshly planed laminations enter the Ledinek Z-Press edge-gluing press. In this step, both the single-layer panels for the longitudinal layers and the boards with several different lengths for what will later be the crosswise layers are produced by narrow-edge gluing. The boards for the crosswise layers are then cut and singulated accordingly using a circular saw. The advantages of the patented Z-Press become apparent on the laying table, which is located in front of the main press. “On the one hand, single-layer panels make it much easier to handle the wood with the vacuum lifter, since twists and curves in the wood can be ignored almost completely. On the other hand, the entire pressing process can be accelerated, since shorter laying times make it possible to use adhesives with shorter open times,” Robert Mlinaric, Head of Sales at Ledinek, explains.

Next, the single-layer narrow-edge glued panels are temporarily buffered on a distribution shuttle with the help of a vacuum lifter. In addition to the main machines in the CLT production process, Ledinek also installed the transport and conveyor technology in between. In order to ensure a smooth process, the machine manufacturer included six buffer spaces directly in front of the press.

The first of its kind

The heart of every cross-laminated timber production line is the central pressing unit. With the XM-Press, a real Ledinek specialty now stands in Portugal. “This is an excellent example of the great collaboration with Ledinek. Our specially designed plant layout included a through-feed press that Ledinek had never built before. Together with Robert Mlinaric and the Ledinek team, we worked meticulously on a solution which resulted in the prototype of the first XM-Press”, Santner says, praising the successful collaboration with Ledinek, and adds: “The entire plant layout was designed within just six months – and it even includes a newly developed machine. Without a competent team and fast, short decision-making processes, this would not have been possible.”

The press used by Arolla is over 6 meters long. “One of the press’s special features is its modular design. The press can be manufactured in steps of 2 meters, from a minimum of 6 meters to a maximum length of 20 meters,” Mlinaric tells us. Depending on the type of press, the maximum width of the standard modules is 2,020 mm. However, due to logistical and production-related advantages, Arolla only produces 1,200 mm-wide elements.

The XM-Press stands for high quality coupled with an optimization of performance and precision, all of which is achieved thanks to even pressure being applied from above as well as from the sides. First, pneumatic pressure build-up from above positions the panel, before additional lateral pressure is applied to prevent the individual layers from shifting. In order to produce surfaces of the highest visible quality, the top layers of the individual elements are slightly wider. This way, the joints are completely closed by the lateral pressing units. Then, the final pressing pressure of up to 1.2 N/mm² is applied, before the panels exit the 6-meter-long press on the other side after a short, optimized pressing time.

For high surface standards

In the next step, a Ledinek Superles 1300 8V+4F planer creates the desired surface finish. The CLT elements are stored temporarily to ensure the complete curing of the adhesive. After that, each element is planed on four sides. “In addition to the precise planing on four sides, the Superles also offers us the possibility to profile the elements in this step. Others have to move them to the joinery machine to do that,” Santner says.

This is possible thanks to eight spindles, which are installed inside the machine to ensure the exact positioning to the required final dimension. In addition to eight cutter shafts, four chamfering units guarantee the precise processing of the elements with cross-sections of up to 1350 x 320 mm. Ledinek’s special exchangeable shaft system also enables particularly short set-up times, since the individual shafts can be driven out of the machine by a motorized drive. The double-sided, 1300 mm-wide grinding unit installed in the Superles planer gives the CLT elements, which are mostly produced in visible quality, the final touch. “The oscillating movements of the surface grinding unit create not only an optimal grinding pattern but also increase the service life of the grinding belts,” Andrej Holc, sales engineer at Ledinek, says about one of the special features of the Superles planer.

At Arolla, the joining is done by a Robot-Drive from Hundegger of Hawangen/DE. This summer, a second joinery machine is to be installed so that the company can fully utilize the capacities and performance of the upstream production line.

“We are glad that we trusted Ledinek with this exciting project. They took our requirements and wishes into account and convinced us with great, customized solutions,” Santner says, who is more than satisfied with his decision to commission Ledinek.

Taking sustainability one step further

In addition to targeted subsidies to the local forestry sector and the gradual increase in the use of Portuguese raw materials, mostly of local maritime pine wood, Arolla decided to not build a new factory but to move into an industrial hall that had been empty for many years instead. “With an indoor area of more than 11,000 m², we have enough space for the entire production and the loading area,” Santner says. After the property had been purchased in the summer of 2021, the necessary changes and construction work began immediately. “The roof was dilapidated and had to be replaced. We also rebuilt and modernized the office and staff spaces,” the experienced engineer adds.

Monolithic building

The central aspect of Arolla’s ideology is a way of building which can do almost without any conventional building materials or other fossil raw materials. An impressive example of how this concept works in practice is Dr. Jakob’s own housing project. From the floor slab to the ceiling, the entire building complex in Santa Catarina near Setúbal consists of solid, 260 mm-thick CLT elements. The idea behind this particularly massive design is to have a monolithic way of building which does not require any insulating materials. The only places in the house where additional non-wood-based materials were used are the wet rooms inside the bathrooms.

“Here, too, the floor and wall elements underneath are made of cross-laminated timber. The diffusion-open design has a particularly positive effect in the wet rooms,” Santner explains. The diffusion-open character of the buildings can be found in all of Arolla’s projects. “This way of building in solid wood does not only work in the mild Portuguese climate. In fact, our projects in Central Europe do not differ in any way from the ones we carry out here,” Santner tells us. In addition to the excellent indoor climate, the massive cross-laminated timber elements can also help reduce energy costs substantially, according to Arolla. Furthermore, the wooden surfaces create a particularly pleasant living atmosphere even in cold winters.

From Portugal to the world

In addition to the existing CAD tools and production planning software, Arolla also programmed its own tool, which supports the entire project management and handling, thereby reducing project lead times significantly. A good part of the company’s revenue is reinvested in research and development in order to further optimize and improve all processes along the value chain. Also, Arolla launched its own “Wood Academy” at the production site in Setúbal to teach employees the necessary know-how. “Here in Portugal, there is no dual training and education system for the wood sector like in Central Europe. That’s why it’s particularly important to us to continuously train our own skilled workers,” Santner explains.

The company’s success proves that the team is heading in the right direction. Arolla’s order books are well filled and the order situation is more than satisfactory. “In addition to receiving many private inquiries, we are also carrying out two large construction projects at the moment. One of them is a terraced house complex consisting of over 60 individual houses in Germany. The second, a holiday village in Portugal near the Atlantic coast, is currently being planned. Starting in the autumn of 2023, more than 11,000 m³ of Arolla CLT will be used for these projects,” Santner says, looking to the future with anticipation.