In order to move towards circular economy in construction sector, existing buildings should be considered as materials banks instead of CDW. Previous researches in Estonia, Finland and elsewhere in Europes have shown that building parts (e.g. wall panels, ceiling panels, posts, beams etc) once produced for a certain functionality might still have acquired properties and reuse potential as a building parts. As most of the CO2 footprint of buildings comes from the main physical structural and building envelope elements, it would be reasonable to keep using these on their original function as much as possible. Majority of buildings by weight in Estonia as well in Finland have been made of concrete, ceramic and silicate bricks, small and large building blocks and other mineral materials that are heavy weight, often contain cement or have been produced by using a large amount of thermal energy (burning, autoclaving). Therefore, reusing building parts (as close to their current location) without any major processing should be preferred instead of recycled as materials (needs transportation as well as processing activity). By doing so, we can still construct „new“ so-called transfer buildings made of building parts from so-called donor buildings. Urban mining (i.e. using CDW from buildings being demolished as secondary raw materials) for new building products also decreases the need for primary raw materials via mining but should seen as a secondary option, if reusing as building parts is not possible.
The future challenge for Tallinn, Helsinki and others cities is to adapt towards climate resilience and sustainability by fulfilling citizens need via circular economy. Although we will build less and try to adapt existing buildings and infrastructure, there will be still need for new construction (and major renovation). Our proposal is to develop following tasks:
- methods to assess reuse potential for existing buildings;
- assessment criteria for quality and properties for parts to be reused;
- technical solutions for deconstruction main typical building types;
- physical and digital material banks concept;
- circularity process for reusing building parts – the process as such, flowchart, its members, connections, responsibility, verification, re-certification etc;
- new business models for reusing building parts.
The aim of the research is to tackle and solve circular construction obstacles in terms of organisational (on city as well as state level) technical, legal and economic aspects, bearing in mind digitalisation of construction sector. Results will be widely scalable and applicable in various sectors of build environment. Also, future skills developed during the projects can be used for the renewal process of teaching curricula in universities as well as for additional training and microqualification for city and landscape planners, architects, consultants, city officials, engineers and other specialists active in a construction sector.