The Rainhof is one of the most precious rural buildings of the Gsiesertal valley (IT), at 1.500 m above sea level. Built with solid stone masonry walls and the vernacular “Blockbau” (solid wood) construction, the building presents many traditional features, such as windows with deep reveals, decorated painted frames around the windows, and vaulted ceilings. The project was awarded the 1st prize at the Bauern(h)auszeichnung - ITAS-Preis 2016 for the best renovation of a farmhouse in Südtirol.
The external appearance of the three main facades are worth of preservation. The ground floor was built in natural stone masonry and still conserved a traditional lime plaster. The window and door openings in the ground floor have deep reveals and are profusely decorated around. The wooden structure of first and top floor built in traditional log construction and the woodwork filigree of the balcony is to be maintained.
The proposed project was developed in consultation and strong collaboration with the heritage office of the province of Bolzano. The project was the result of a series of meetings and discussions between all the parts involved. Initially, an onsite building survey was carried out with the building owner, architect (Dr. Arch. Stefan Taschler - archilab) and a representative of the heritage authority. The open dialogue and the mutual support between building owner, architect and heritage office ensured the quality of the retrofit, promoted the valorisation of the heritage and reassured the building owner that the design was going to be in coherence with local construction regulations and high standards of quality and comfort in the building.
The Rainhof was extended with one apartment on the ground floor and two holiday apartments on each of the floors above. The aim of the project was to preserve the overall appearance of the listed building but to enable contemporary living and working. The owner and architect were convinced from the beginning that a general renovation of the building should also include an increase in energy efficiency and comfort of the building.
Most of the stone-masonry wall in the ground floor was insulated internally with a thin layer (4-6 cm) of insulating plaster (Calcetherm λ=0,068W/mK). The U-value was improved from 2,39 W/m2K to 0,87 W/m2K (based on standard values of the energy calculation tool). This insulating plaster is lime-based and, unlike an insulating panel, it is applied in a thin layer that can follow the uneven surface of the original wall surface ensuring a similar appearance to the original plaster. The existing solid wood construction, consisting of horizontal rectangular hewn beams and wooden panelling was insulated from the inside with 12 cm of wood fiber board. In addition to the thermal resistance improvement (from 0,64 W/m2K to 0,24 W/m2K) the addition of a windproof layer between the old structure and insulation panel improved significantly the air tightness of the whole construction.
All existing windows were exchanged with new units made ad-hoc. The aim was building a two-sash window with two glazing bars each that achieved high levels energy performance as well as be of high aesthetic quality.
In terms of renewable systems, space heating and domestic hot water is provided by two different boilers, both running with renewable energy. The biomass boiler uses wood chip produced directly from the farm woodland and stored in the silo next to the building. The gas boiler runs with the biogas produced from the manure of the cattle reared in the farm in a biogas plant built between the stable and residential building. The energy produced from biogas and wood chips cover the energy need of the Rainhof, a nearby house (included holiday apartments) and the stable.
The consumption estimation after energy efficiency renovations: 60 kWh/m2.y (energy calculation Energy calculation tool of the local energy label ProCasaclima).
Further information can be found here.