Renovation of an old mill

Product: BauBuche

With the renovation of the listed grain mill in the town of Hann. Münden in Lower Saxony, ten private flats with an area of up to 180 m² were built. The old wooden beam ceilings were especially challenging, because their bearing capacity was at risk of overloading. Thanks to the high compressive and tensile strength of BauBuche, the renovation work could be completed in narrow dimensions with excellent fire protection properties and the monument value of the building could be retained.



Bernd Demandt

Construction location

Hinter der Stadtmauer 9 und 11

Architekt / Designer
Structural engineering

Conny Jordan, Münden

Carpentry and wood construction

Zimmerei Franke-Lotze, Münden / Zimmerei Grünewald, Münden / Holzbau Meyer Surup, Münden

Construction area

1100 m²

New living area

950 m²

Total cos

1,350,000 €


Diana Wetzestein

"The installation took somewhat longer in this case, but now we know how we have to work with the material. The high-strength beams are absolutely recommended for renovation work on girders, gates or building passages. And with the amount of material saved in comparison with coniferous wood, the price-performance ratio is also beneficial!"
Michael Franke, Master carpenter
Zimmerei Lotze

Listing and history of the building

The vaulted cellar under the grain mill was constructed at the turn of the 14th to 15th century. The building was later built above it in 1796 and 1888. The building technology was last modernised in 1917/1918, but then fell victim to a large fire within a few months. Over the course of the 20th century the building was used primarily as a warehouse for spirits and the stood empty since the mid-1990s. Thanks to the dedication of preservationist and hotel operator Bernd Demandt, the historical grain mill was given a new lease on life. He decided to renovate the building in consideration of its listing as a historical site and to create a new living space for ten residences.


Renovation of the supporting structure with BauBuche

Since the specified storage height was more than doubled in the past, the old coniferous wood beams (30×30 cm) between the upright and supporting surface were compressed several centimetres transversely to the fibre. Despite bolstering with oak boards and steel sheet, the supporting structure had to be replaced in the scope of the renovation work.
Oak beams were originally planned for the ground floor – however, this solution was infeasible due to unavailability.

BauBuche was ultimately chosen because of its excellent material characteristics. Based on the high compressive strength transversely to the fibres, the support cross-sections on the ground floor could be significantly reduced.


Field report – Carpentry

Assembly of the BauBuche supporting structure was carried out by Zimmerei Lotze-Franke in collaboration with Zimmerei Grünewald and the wood construction company Meyer Surup, who were working with BauBuche for the first time. Using chain hoists, the beams (4m x 24 cm x 28 cm) were raised and anchored in place. ‘The joist hangers had to be pre-drilled,’ explained master carpenter Michael Franke. ‘It was not as easy to simply screw in the screws as we could do with coniferous wood beams.’ This is due to the high raw density of the beechwood, which also provides good compressive strength and a high bearing capacity – unlike coniferous wood veneer beams, which would have to have much greater dimensions to provide the same properties.

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