Production of glued cross-laminated plate element with rib

Location: Celje, Slovenia

Contact: dr. Bruno Dujič

Tel: +386 41 842 752



Estimated value: Other


In the innovative contemporary sustainable wooden construction, cross-laminated panel systems (Xlam) are becoming more and more established. Due to layering varsity, cross-oriented lamellas and thicknesses, Xlam is used for all types of structural systems of buildings in the last period also for buildings over 10 storeys. In this type of construction system in most cases high consumption of wood as basic raw material is used for the production of solid cross-laminated panel elements. Depending on the implementation process, an optimization is proposed, where the ribbed layer is embedded in one side as the outer layer on a solid crosswise wooden two or multilayer element, where the position or distance of vertically set up wooden lamellas or ribs is designed and constructed according to boundary conditions as are load-bearing capacity and deformability, with respect to other requirements as are vibrations and following upgrades of Xlam construction with other finalization layers. Upright oriented lamellas or ribs are glued between two adjacent flat glued lamellas on the below crosswise oriented layer. Such process of adhesion and compression is forming U joint between the rib and adjacent lamellas which guarantees the robustness of the glued structure. In particular, the U joint is crucial in the manufacture of the product to ensure the stability of the rib in the compression process and the final bearing capacity of the bonded joint. Standard Xlam production line can be upgraded with a “by-pass” production line, where the upgrade of cross-laminated plate elements with ribs can be performed. This would save 20% to 35% of the raw material on the wall and plate elements. The ribbed elements would have also better mechanical properties despite lower wood consumption, while the ribs would be an upgrade on the basic lamination of crosswise wooden layers what is now performed on the construction site and caused increasing of construction costs. An important area of optimization of the construction process is the upgrading of exterior walls with large insulation thicknesses, which usually require a wooden substructure, which could now provide ribs embedded in the basic structure of the cross-laminated timber wall elements. The ribs integrated into basic Xlam plate element would also mean a great savings in material consumption and the reduction of the number of layers in multilayer element to achieve the required load-bearing capacity, deformability and vibration limits, since by increasing the static height of the ribbed element better geometric and mechanical properties would be achieved. In addition to the great material savings, there is also a cost savings in the production process by reducing the number of required layers, from usual 5-layer plate elements now 3-layers would be sufficient when producing ribbed elements.

Read more about the opportunity in this Research Paper: Less is more, optimized ribbed CLTs the future.

Benefits for investor

Slovenia has wood raw material, which is currently largely unused in the processing process and is therefore mostly exported. The biggest potential in wood processing is the construction sector, where there is no manufacturer for cross-laminated wall and plate elements in Slovenia. Thereby a great market opportunity for the investor is already the production of cross-laminated wooden elements with the possibility of upgrading production into ribbed cross-laminated wooden elements. This would also increase the manufacturer’s competitiveness in the foreign markets, since the upgrade is protected by an EU patent.

Investment value

Estimated investment value: The amount of investment depends on the size of production program (logs – raw material – dry wooden lamellas – finger jointing line of lamellas – production of Xlam wall and plate elements – production of Xlam ribbed wall and plate elements, CNC processing, additional other works on Xlam surfaces). The production base is, according to the technology, an optimal production hall with properly equipped transport routes, where the key routes should be covered with bridge cranes. Ground base for the production process is a dry wooden lamella, therefore it is necessary to check the raw material base and proximity of required raw material input for the beginning of the technological process for the implementation of the cross-laminated element with ribs. It is necessary to consider whether the investment plan also includes a sawmill and drying chamber, or whether the investment starts from here further. In the production technology of cross-laminated wall and plate elements, it is necessary to determine the optimal size of production for the walls and the plates according to different boundary conditions.
The basis for the beginning of the production process is the longitudinally joining (finger-joint line) of the wooden lamellas, the preparation of the lamellas for gluing, stacking wooden lamellas into a crosswise layered structure and the by-pass line for upgrading the last layer with a ribbed structure before the final compression. In the production process of Xlam element with ribs it is necessary together with the vertical compression assure also a side pressure with compression on last ribbed layer in lateral direction. After the gluing and pressing process, it is necessary to provide surface treatment and CNC cutting with loading the elements onto the truck trailers and containers.
The investment value is therefore highly dependent on the volume of the entire production process and ranges from 5 million to 50 million euros for the implementation of the latest highly-developed technological line in the full scale.

Desired form of investment and possible conditions

Not defined, discussion with investor required.

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Development strategy

The proposal contributes to the achievement of objective no. 6 Slovenia’s Development Strategy 2030 by promoting the development of science and research in priority areas and the transfer of research achievements to a highly competitive economy; Objectives No 7, through the creation of quality jobs that create higher added value, are environmentally responsible and provide the conditions for adequate pay and a quality work environment; Goal 8 by promoting innovation to develop new business models and products for the efficient use of raw materials, energy and adaptation to climate change. The proposal also envisages the creation of dozens of direct new green jobs once production is established.

Forest-timber chain activity

Wood working and processing.

Type of investment

Modern technology, equipment or infrastructure,

development of developmental and technical-technological solutions in the priority area of ​​application of the smart specialization “Smart Buildings and Home with a Wood Chain” (smart houses, furniture, etc.),

development of solutions that will enable environmentally friendly and safe timber construction,

sustainable development solution, circular economy, new business models,

other technical and technological solutions or services related to the forest-timber chain. Please specify: Establishing a forest-timber-construction chain as a priority for the industry development.