Pyörre House is a steel-framed single-storey detached house built for the Lohja Housing Fair in 2021. The building has 227 m² of floor space and the primary construction is made of steel. The house has been designed and constructed to embrace low carbon circular principles and strategies, of all the materials used on the project, it is made up of 22.1% recycled, 15.3% renewable and 62.6% non-renewable materials. The design team carefully mapped the use of materials and building components for the project, exploring ways in which the building could retain its value and usefulness over the long term.
An evaluation of the building was carried out during the design and construction phases, before taking the building into use. At the time of the evaluation, there were no official methods for assessing the circular economy of buildings and there were few methods in Europe that were suitable for a quantitative assessment of circularity. Therefore, the assessment of circularity was based on a combination of three complementary assessment methods: EU´s Level(s)1, German DGNB2 and the Building Circularity Tool of OneClickLCA software, with this combined method, it was possible to quantify both climate burdens (carbon footprint) and potential climate benefits (carbon handprint).
Assessment for the ease of disassembly and for the utilisation of disassembled products and materials has been made based on design documents. Although the utilization would take place in the future, its potential has conservatively been estimated according to today’s practices. For example, the load bearing frame made up of steel, gluelam and timber parts are attached to each other with screws and attachment plates and within the assessment of the utilisation potential of these building parts, opportunities were identified for the reuse of components, the recycling of steel and energy recovery of wood.
The project has been included within the Ministry of the Environment’s low carbon construction pilot programme, specifically created to develop a set of suitable criteria through which buildings of all types (including residential) could assess its carbon footprint and carbon handprint, where carbon handprint is the positive actions taken to have a positive impact on the climate — the opposite of footprint. The carbon handprint of the building is almost as high as its carbon footprint. This is due to the good recyclability potential of the chosen building materials, especially regarding steel components.