Green City L23 was the first four-storey building with residential and commercial units in the Bad Tölz / Wolfratshausen district in Germany constructed exclusively in timber and optimised for energy efficiency. Even the lift shaft weighing 30 tons is made in timber – a feature that was close to the heart of the developers Tilmann Vorholz and Georg Hawran who wanted to show that wood can be used for virtually any type of construction.
For Tilmann Vorholz and Georg Hawran, building in steel and concrete is never an option, as the trained carpenters have made it their mission to design their low-energy houses in the most sustainable construction material available: timber. In order to show prospective clients what their work is all about, they each built their own passive house in 2001. In 2014, they joined forces and funds for the "Green City" project consisting of a production hall and a carpentry shop, as well as various residential units, workshops and office spaces. The highlight of the complex is the four-storey section for which Tilmann Vorholz and Georg Hawran chose BauBuche, which at the time had just become available on the market.
The BauBuche beech laminated veneer lumber was used for all support structures of the building. Thanks to the slim and strong BauBuche GL70 beams, the four-storey construction could be dimensioned much larger than would have been possible with conventional softwood. The developers loved the veneer look of BauBuche and therefore left columns and beams exposed.
Although there are some extra costs associated with the machining of BauBuche – for instance because the material must be protected against moisture and all connecting points for fasteners must be pre-drilled – Tilmann Vorholz still thinks that they made the right choice. He is delighted with BauBuche, as it provides a viable alternative to steel and concrete.