DGNB certificate for deconstruction in Switzerland

Where until a few years ago there was a grain silo tower from the 1930s, today an elegant residential tower with a 30-metre-high solar façade rises into the Prättigau sky. Grüsch Mill in the Grisons municipality of Grüsch is Switzerland's first DGNB-certified reconstruction project. No objections, no compromises and a building concept that has been consistently thought through to the end.

The grain silo tower from 1939 was demolished, but its concrete was not disposed of. In the nearby concrete plant, the material was processed according to a specially developed formula and 75 to 95 percent of it was reused as recycled material in the new building. Around 60 percent of the new building consists of the old tower. The client is Gutgrün AG from Chur, which deliberately refrained from making short-term profits in order to consistently implement the sustainability concept.

52 apartments, three certificates
The project comprises 37 rental apartments on eleven floors in the new residential tower and 15 loft apartments in the renovated historic mill building. The architects from Ritter Schumacher have recorded all the materials used in a building resource passport. A forward-looking approach that makes future life cycles transparent today. The project was awarded three DGNB certificates for this achievement. DGNB Platinum for the demolition, DGNB Gold for the new tower and DGNB Gold for the refurbishment of the old building.

Fire protection reinvented
The 30-metre-high photovoltaic façade poses a problem for conventional fire protection regulations. They require partitions on every floor to prevent fire from spreading from floor to floor. This would have interrupted the façade and significantly reduced its efficiency.

The PV surface is not interrupted anywhere by windows and is continuous from the floor to the roof. Specialist planners, contractors and the insurance company worked together to develop a tailor-made solution. Fire cannot reach the façade from the inside and the façade cannot reach the apartments.

Alliance instead of conflict
The project was built using the alliance model. The client, planners and contractors sat around the table together right from the start. Problems from construction practice were thus incorporated directly into the planning. The basic attitude was one of trust and fairness rather than pure risk hedging. One detail also testifies to the unconventional spirit: the graffiti that adorned the vacant building was retained as decorative elements in the stairwell.

A signal for the industry
There was not a single objection to the conversion project. This is unusual for a construction project of this size. Grüsch Mill shows that circular construction also works in a peripheral region and that sustainability is not a contradiction to economic viability.