In just 55 days, this four-storey, mass timber residential block consisting of 41 units and wooden elevator shafts was erected. The project demonstrates a very high level of prefabrication, partnership and the use of in-factory services for optimal installation and moisture management.

Located in Würzburg, in northwestern Bavaria, Germany, along the banks of the Main River, approximately 100 km southeast of Frankfurt am Main this project is part of the development of a new district called Hubland.

The Hubland area is being transformed into a vibrant residential and commercial zone, featuring modern housing, educational institutions, and recreational facilities. The development includes several distinct quarters, each designed to offer a high quality of life with ample green spaces and sustainable urban planning.

Timber construction

The timber construction design phase for this residential project began in the spring of 2022 and involved close collaboration with planners specialising in fire, acoustics and structural calculations.

The primary objective during this predesign phase was to optimise the use of raw timber in the construction materials, including the supporting structures. This collaborative approach resulted in a high degree of cross-laminated timber (CLT)being used in the supporting structures and in the internal walls, floors, roofs, lift shafts, and stairway walls, which contributed to the properties’ overall low carbon footprint.

Partnership

was key to the success of this project. Stora Enso provided the standardised kit of parts while Holzunion handled the further prefabrication of the facades and lift shaft. This collaboration ensured that the project benefited from the expertise and specialised services of both companies which we explain in more detail here. HolzunionThe partnership between Stora Enso and

Prefabrication and assembly

Prefabrication: The components utilized 1,352 m³ and Floors that were first manufactured by Stora Enso in their mill in factory-controlled conditions with precision and then transported for further processing by Holzunion. Sylva™ CLT Walls

. Given the construction period Temporary Membranesand End Grain Sealer  and applied Sylva Protect ServiceThe project took advantage of Stora Enso's (25.08.2022 till 19.10.2024), was during a wet German autumn, the additional layer of protection played an important role in the overall moisture management plan.

Sustainability

The Sylva kit generated 26 tonnes of greenhouse gases (CO₂e) to manufacture and 19 tonnes of CO₂e to transport. Compared to the 379Stora Enso Carbon Calculator). tonnes of carbon dioxide that the trees removed while growing and will store in the building, this is a small fraction. Choosing Sylva CLT elements instead of non-renewables avoided 568 tonnes of greenhouse gases. (Source:  

Decarbonising the built environment - Wood Products | Stora EnsoExplore more:

Integration: adding façades, windows, and integrating insulation. They assembled the elevator shafts and so they could be installed as a single element. 2,500 m² of exterior wallsHolzunion added additional layers of elementation to the

Transportation: The prefabricated elements were then transported to the construction site using just-in-time delivery service, so that the right elements arrived in the right sequence for installation. This service eliminated the need for onsite storage and reduced the amount of time that the elements were exposed to wet weather conditions.

Assembly: On-site, the prefabricated elements were safely manoeuvred directly off of the delivery vehicles by Karl Hoffmeister GmbH and Holzbau Taglieber GmbH and into position, considerably reducing the number of on-site labour hours. All interior and exterior walls of the ground floor were in place within one week.

Timeline

Frame erection period from 25.08.2022 till 19.10.2024

The project was completed within the planned timeframe with the client taking possession in 2023.  The project adhered to Class 4 German building regulations.

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