The Triodos Vastgoedfonds purchased old office premises in the centre of Groningen in order to carry out a fully-sustainable renovation. The building’s energy usage label changed from G to A+and was leased with a green lease contract to GasTerra, a commercial enterprise that operates at an international level in natural gas. In addition to its highly negative energy consumption, the building, completed in 1986, lacked a robust architectural appearance and the architectural detailing was extremely poor.
Beside the aesthetic motive, all the interventions in the existing building had an energy-saving objective. By reducing the abundance of details and solutions, the corner premises near the central station gained a more univocal visual image. A new, atrium in the heart of the building not only created a central meeting place on the ground floor, but also sight lines between the floors and daylight in the entire building. The reduction in the volume of auxiliary equipment in the building created space on the roof for a new representative area with a panoramic view of the city. Upgrading the insulation value of the exterior wall would have required total demolition and replacement of the existing brickwork and insulation. At a material level this was not the most sustainable solution. After studying the problem together with the installation consultant, it was ascertained that this could be achieved by fitting new window frames, including triple glazing, and installing solar panels and a cold-water storage system coupled to an extremely efficient gas heat pump.
Inventive solutions and ways to avoid demolition were developed in close dialogue with the client and consultants. On the one hand this has resulted in an upgrading to energy label A+ and, on the other,in an attractive, spacious and open office building. Moreover, an EPC value of 20% under the current regulation system leads to “green financing” and an official “green declaration” from Agentschap NL. These renovated office premises not only contribute to driving back the use of fossil fuels, but also provide an attractive and effective answer to the problems surrounding long-term office vacancies.