Five-storey “Sägen 6” in Dornbirn showcases LVL & solid beech (BauBuche) excellence

 Wednesday, November 12, 2025

In the town of Dornbirn in Austria’s Vorarlberg region, the innovative five-storey office building Sägen 6 represents a new milestone in engineered timber construction. Designed by the resident firms Johannes Kaufmann Architektur and merz kley partner ZT GmbH — who also occupy the offices — the building relies heavily on the high-performance engineered hardwood material known as BauBuche, alongside a central service core made of cross-laminated timber (CLT), to deliver both structural efficiency and architectural clarity.

BauBuche is a laminated veneer lumber (LVL) product manufactured from solid beech wood (Fagus sylvatica) that offers high compressive and bending strength comparable to engineered soft-wood elements, yet brings the aesthetic and tactile qualities of hardwood. In Sägen 6, approximately 63 m³ of BauBuche were used in the load-bearing structure, and about 200 m² of BauBuche panels were applied in interior finishes.

Thanks to BauBuche’s exceptional load-bearing capacity, the structural design could adopt slimmer post-sections and optimise material use. According to case documentation, the BauBuche posts are 40 cm wide and 32 cm deep along the central axis, transferring vertical loads directly from column to column — without lateral thrust onto beams or floors. This optimised load transfer is a hallmark of efficient timber frame design using hardwood LVL components.

The building’s service core — housing stairs and elevators — is crafted from prefabricated 20-cm thick CLT elements. This mass-timber core functions as the vertical stiffening element for the structure. Attached to this central shaft are BauBuche beams and the CLT floor slabs.

The construction follows a timber-skeleton or timber-frame principle: vertical loads flow from floor to beam to post and ultimately to foundation, with minimal lateral load paths and efficient direct load transfer. As one project note explains: “vertical loads on all axes are transferred through end-grain joints directly from post to post, preventing lateral thrust on floors and beams.”

Architecturally, Sägen 6 presents a clear structural grid, visible BauBuche columns along the central axis, and a façade clad in planar spruce panels with a weathered grey finish.  The exterior also features high-performance insulated timber-frame wall elements, while the basement and underground parking are constructed in reinforced concrete, serving as a stable base for the timber superstructure.

Each floor offers approximately 350 m² of flexible office space that can be subdivided into open-plan or partitioned layouts without constraint from load-bearing walls or beams—a design made possible by the structural efficiency of the BauBuche-CLT system.

For manufacturers and specifiers in the engineered wood sector, Sägen 6 provides a strong case study on the application of LVL solid-beech (BauBuche) and CLT in multi-storey timber structures. Some of the implications for the wood-products industry include:

• Material efficiency: Using high-strength LVL hardwood allows for smaller component sizes, reduced material usage, and optimised load paths.
• Aesthetic value: BauBuche’s fine grain and hardwood character offer enhanced interior finishes and architectural appeal—a bonus when specifying visible timber.
• Market differentiation: Projects like this demonstrate the viability of hardwood‐based engineered products in higher-storey construction, expanding opportunities beyond conventional softwood CLT and glulam systems.
• Integration and prefabrication: Prefabricated panels and a timber skeleton enable faster on-site assembly, improved quality control, and reduced site disruption—a strong selling point for producers of engineered timber elements.
• Sustainability narrative: Built using wood from regional sources (in this case, the façade timber came from the owner’s own forest) and engineered timber systems, the building aligns with low-carbon construction goals.

Overcoming challenges

As with any advanced timber construction, Sägen 6 presented unique design and construction challenges. Among these were:

• Ensuring fire-resistance (the building falls under fire-safety class F90/REI90) while using timber elements—achieved via fire-protected CLT core and BauBuche components enclosed or treated appropriately.
• Precise coordination of load transfer details and prefabricated connections, especially where beams are suspended from posts, and avoid lateral thrust on floors.
• Integration of timber structure with base-concrete basement and underground parking, requiring careful connection design and interface detailing.
• Acoustic, fire, thermal, and service integration within a primarily timber structure, addressed via micro-perforated panels for acoustics, high-performance insulation in wall elements, and engineered detailing for services.

Lessons for timber product manufacturers

For producers and suppliers of LVL solid-beech and related timber products, the Sägen 6 project offers valuable takeaways:

• Positioning hardwood LVL (like BauBuche) as a high-value alternative to softwood engineered elements can open up premium segment use-cases.
• Demonstrating multi-storey timber buildings increases demand for engineered hardwood products and supports higher yield per unit area.
• Collaboration between architects, structural engineers, and timber-product suppliers is crucial early in the design phase to unlock the benefits of high-strength engineered timber.
• Emphasising the visible aesthetic qualities of engineered hardwood provides an additional marketing point beyond structural performance—particularly for office, hospitality, and showroom applications.

The five-storey Sägen 6 building in Dornbirn stands as a benchmark for modern timber construction, combining high-performance LVL solid-beech (BauBuche) components, CLT mass-timber cores, and a timber-skeleton structural system to deliver elegance, flexibility, and sustainability. For stakeholders in the engineered wood products industry—especially those focusing on hardwood LVL, CLT, and high-rise timber construction—this project perfects the integration of architectural design, structural engineering, and advanced timber materials.

As demand for sustainable, high-performance timber buildings grows, the insights gleaned from Sägen 6 will help timber-product manufacturers, specifiers, and construction firms refine their strategies, expand their offering, and position timber as a premium choice for the next generation of vertical construction.

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Tags: BauBuche timber engineering, CLT timber service core office building Austria, engineered hardwood LVL solid beech construction, LVL solid beech building Austria, Sägen 6 Dornbirn five storey timber, timber frame high-rise office Germany Austria