European Patent Office renovation uses Holcim’s sustainable building solutions

Standing close to Vienna’s iconic Belvedere Palace in the city’s historic center, the European Patent Office (EPO) building has been renovated using sustainable building solutions from Holcim – ECOPact, ECOCycle and Elevate – to create one of Austria’s most iconic buildings.

Stunning new office spaces are transparent and open, with glass providing bright, lively rooms and visual connections with the outside space. Yet the renovation of the 50-year-old building goes beyond aesthetics: it was designed to be one of the most sustainable buildings in Austria.

The project uses only ECOPact low-carbon concrete with ECOCycle inside to reduce construction emissions and drive circular construction, while Elevate Isoguard^TM insulation contributes to the building’s energy efficiency in use.

The vision

EPO ran a feasibility study in 2019, and decided that its current Vienna building had reached the end of its operational lifespan. While the study recommended redeveloping the site with a new building, the EPO took the more sustainable approach of stripping the office back to its original concrete skeleton, for a reconstruction based on the plans of ATP architekten ingenieure.

With 80% of Europe's building stock projected to still be in use by 2050, repairing and renovating buildings with green retrofit systems is one of key levers we can use to decarbonize the built environment and achieve the European Union’s net-zero targets.

Since the EPO building lies in Vienna’s historic third district – close to the Belvedere Palace, Salesian Monastery and the university Botanical Garden – the design of the renovated building needed to seamlessly blend in with the city’s rich architectural traditions.

The solution
 

To help achieve the project’s sustainability vision, Holcim created bespoke innovative and low-carbon ECOPact concrete mixes for PORR. These offer a minimum of 30% lower CO₂ emissions compared to standard concrete, with approximately 1500 cubic meters used.

In addition, the ECOPact mixes developed for the renovation uses Holcim’s proprietary ECOCycle circular technology. Harnessing this we are able to recycle construction demolition materials (CDM) – from cement and aggregates to concrete – into new, high-value building solutions.

One of the ways PORR, the construction company behind the renovation project, made the building more Vienna branch of EPO sustainable was through use of renewable energy and energy recycling. Solar collectors generate more energy than the building consumes, with the surplus energy then fed into the electricity grid.

Heating is provided by 20 geothermal probes that feed a heat pump. Additional energy demand is met by the large-scale photovoltaic system and storage batteries.

For the building’s roof and arcades, PORR used Holcim Elevate’s Isoguard™ AK PIR insulation to boost the building’s energy efficiency in use, facilitating its heating and cooling. These boards offer the same thermal performance as thicker and/or heavier insulation materials, allowing solar panels and heat pumps to be installed on the rooftop to meet the building’s power needs in full.

The icon

During the renovation process, the embodied carbon of the ECOPact was 38% less than traditional concrete, while primary material use was reduced by 26% thanks to the use of ECOCycle construction demolition materials in the mixes.

The renovated building produces more energy than it consumes to deliver heating, cooling, ventilation, lighting and hot water. As a result, Vienna’s EPO building received the highest Building Research Establishment Environmental Assessment Method (BREEAM) rating in the DACH region, and serves as a lighthouse example of a sustainable renovation with Holcim’s solutions inside.