Sustainability Report

Efficient

Sustainability was embedded in the project through the decision to retain, refurbish, and extend the heritage-listed building rather than demolish it. The rooftop extension increased the building’s volume by approximately one third while retaining the embodied energy contained within the existing structure.
The new storey uses a lightweight timber construction for its load-bearing structure, floor slabs, and roof. Together with dry screeds, this reduced additional structural loads to a level that the existing building could accommodate without substantial reinforcement. The approach also reduced material consumption and avoided more extensive structural interventions, including strengthening that would otherwise have been required to meet the highest seismic safety requirements.
Extending the building vertically rather than increasing its footprint also kept the degree of intervention to a minimum and formed part of the project’s strategy for conserving resources.
Volet carried out the timber works; JPF-Ducret, under contract to Volet, supplied the timber and manufactured the metal fasteners. These were designed to meet the civil engineer’s requirements, including concealed fasteners, timber-to-timber connections, and ball joint, and recessed joints. The timber was specified to appearance class N, using GL24h structural timber.
Argolite HPL 0.9 mm by Argolite AG, specified in UNI 324 Creme with an Alumatt (AM) surface, was used to laminate the new technical surfaces.

Efficient

The existing facades were upgraded internally with blown-in cellulose insulation, improving their thermal performance while preserving the building’s original architectural expression. External insulation was ruled out because it would have altered the appearance and heritage character of the facade.
The refurbishment also included the replacement or upgrading of glazing and the treatment of thermal bridges. These interventions were undertaken from within to minimise changes to the protected exterior.
The new rooftop extension met Very High Energy Performance (THPE) requirements, while the existing historic structure was refurbished in accordance with Minergie Renovation standards. This differentiated approach was used to reduce energy consumption while preserving the building’s heritage fabric.
Heat is supplied through the SIG district heating network (CAD SIG), replacing the building’s former oil-fired boilers. The highly insulated green roof of the new extension also incorporates a photovoltaic installation.
Energy calculations carried out following the renovation indicate a significant reduction in energy demand as a result of the upgraded building envelope, connection to the district heating network, and photovoltaic system. The available calculations primarily address operational energy consumption and associated carbon emissions.

Argolite AG