In developing the tenant-owner association Viva in Gothenburg, Riksbyggen’s goal has been to create Sweden’s most innovative building project with a focus on sustainability. By thinking innovatively about concrete, they have identified methods to reduce the project’s carbon footprint.
“This project was intended to demonstrate how we can reduce climate impact. And we have seen that it really is possible,” says Nadia Al-Ayish of RISE.
The Viva Estate is located high up in the Johanneberg district of the city. Riksbyggen has maintained a major focus on sustainability throughout the planning and building process. Among other things, this has resulted in the tenant-owner association having their own solar-cell installation, with energy stored in second-hand bus batteries. Another important element of the project has been to reduce the residents’ need for private cars, and the estate will not have any residents’ parking spaces.
With regards to the construction itself, the use of concrete has been reviewed from top to bottom.
“Riksbyggen has taken on overall responsibility and has seen an opportunity to influence future projects. They have done so commendably and we have been able to participate and assist them within our own areas of expertise,” says EvaLotta Kurkinen of RISE, project manager for Criteria for Resource-efficient Construction in Practice.
Concrete offers unique characteristics for buildings and civil engineering; characteristics that are in many cases irreplaceable. It is therefore important that we work continuously to develop the material to reduce its environmental impact and make its production resource efficient. At an early stage, the Viva Estate project addressed issues such: How do we build without using unnecessary amounts of concrete? How do we find a recipe for concrete with a smaller carbon footprint? How can transport be reduced?
Gradually, smarter solutions have emerged, with RISE continuously conducting life-cycle analyses to measure climate impact.
“For example, Riksbyggen set the demand that concrete should contain a smaller percentage of clinker than normal. If we look at the chosen recipe, we can clearly see a major environmental profit,” says Nadia AlAyish.
Rebar and remesh also play an important part. At the Viva Estate, this has been manufactured from scrap and recycled materials.
Life-cycle analysis of building projects is similar to detective work; it is necessary to follow up all mixes, materials and promised transport solutions to ensure that specified requirements have been complied with.
“If you set environmental requirements and ensure that these are met, then a significant amount of concrete’s climate impact can be eliminated. Viewed across its entire lifespan, its carbon footprint is comparable with timber. This naturally arouses interest,” says Nadia AlAyish.
A life-cycle analysis measures the full range of impacts over all the phases of a building's useful life. That is to say, from production until it is demolished, stored or recycled. In this project, measurements have been taken in total kilograms of CO2 equivalents per square metre of living area. Working life has been set at 100 years.