Between 2007 and 2008, the mill in Oberhallau, built in 1609, was completely renovated. Until 1890, the mill was operated with water and even until 1995 the building was used as an actual mill. As part of the renovation – in addition to a completely new water supply and disposal, new electrical systems, the replacement of the roof, windows and floors – also an air-source heat pump was installed to heat the building and the outer walls were insulated . For this purpose, Spaceloft aerogel blankets were used in the first façade restoration with aerogel in Switzerland. The aim was to prevent moisture damage in the building due to condensation on the cold building structure and create a higher surface temperature indoors at the same time. This leads to a higher thermal comfort in the rooms. The walls of the building consist of approx. 90 cm of quarry stone, so that the walls had a u-value of approx. 1.7 W/(m²·K) before the renovation. The energetic upgrade of the façade by Amstein + Walthert with two layers of Spaceloft blankets of 10 mm thickness each and 30 mm thick plaster led to a reduction of the U-value to approx. 0.48 W/(m²·K) .
For this measure, first a mortar layer was applied to the dry-stone wall. While this was still wet, the aerogel blankets were installed, which were additionally fixed with plastic dowels. Then the insulating render was applied with a mesh, followed by a finish render.