Circular economy in construction – what to consider from planning to construction

Promoting environmental protection through sustainable construction: The circular economy, in the sense of valuable recycling of raw materials and construction, is an essential tool for the sustainable design and development of urban areas.

The building laws and regulations of the federal states contain specifications and objectives for the design of buildings. With the 2023 amendment to the Vienna Building Regulations, resource conservation was enshrined as an additional objective of urban planning for the sustainable design and development of urban areas, as was already the case in the Styrian Building Regulations. Sustainable construction has taken on a very special significance in this context.

Sustainability in construction – now mandatory?

The building regulations for Vienna stipulate that when establishing and amending zoning plans and development plans, consideration must be given to promoting the sustainable use of natural resources. Urban planning is therefore required to focus more on the continued use and preservation of existing buildings and the avoidance of new construction in line with this objective. Urban planning can make use of the respective development plans as an efficient implementation measure. These can be used to reduce building density and specify qualities that must be taken into account when constructing buildings, particularly with regard to the conclusion of urban development contracts. Redensification can also be slowed down by specifying maximum sealing levels. This instrument also makes already sealed areas, including buildings, more attractive for project developments.

The possibilities for sustainable construction and resource conservation are set out in the legal provisions of the Recycling Building Materials Ordinance, the Construction Products Ordinance, and the AWG. Sustainable construction is therefore an interplay between building law and waste management regulations. 

Scope of sustainable construction

The efficient use of resources plays an important role in both new buildings and existing structures. Existing buildings can be reused or upgraded, for example, by renovating them with reused and recycled building materials. In addition to reducing the consumption of material resources, this also avoids the emissions of new “embodied” CO₂. Resource-saving demolition of buildings is also part of sustainable construction. 

An essential aspect of sustainable construction therefore lies in the planning phase, which pays particular attention to the durability and reusability of materials and components.

Resource-efficient – but how?

Although resource conservation in the sense of the circular economy may seem complex and somewhat daunting to the general public due to terms such as “recycled building materials” or “reuse of waste,” it should be noted that a movable object is already considered waste if the owner wishes to dispose of it (subjective definition of waste). Accordingly, even functional movable objects can be classified as waste.

The direct reuse of such functional “waste” is considered a sign of efficient use of resources. For example, “products” resulting from demolition work can be used directly for other purposes or prepared for reuse. In the case of the demolition of a building, this includes, for example, the reuse of spiral staircases, doors, radiators, sanitary ceramics, or floor coverings. These can be installed directly in new buildings or handed over to specialist companies, which can “manufacture” them into functional products again (preparation for reuse) by testing, cleaning, and repairing them. Conserving resources can therefore not only save money, but also promote sustainable construction. 

However, it is not only spiral staircases, floor coverings, and similar items that can be reused in demolition work; building materials can also be recycled in accordance with the Recycling Building Materials Ordinance. Recycling waste is a process in which waste material from products is processed either for its original purpose or for other purposes. This has the advantage that the materials from the demolition can be checked for reuse directly on site. For example, recycled building materials can be used for planned roads and paths or, in large construction projects, as an additive for concrete production as recycled concrete material. This is not only a matter of maximum resource conservation, but also an exemplary implementation of a circular economy: A building is demolished, the resulting materials are “recycled” and used directly on site for the new building. The cycle from creation to recycling of the “waste” can be closed on the basis of a single building without significant additional effort.

Conclusion and outlook

At present, neither the provisions of state building laws nor the provisions of the Recycling Building Materials Ordinance, the Building Products Ordinance, and the AWG impose any obligations on building applicants to construct buildings in a sustainable manner. However, it is to be expected that in future, sustainable construction and resource conservation will also be made mandatory on the basis of the required qualities when urban development contracts are concluded. In addition, sustainable construction will also play an important and mandatory role in building permit procedures.

In summary, it is clear that the implementation of a sustainable circular economy requires close interaction between building and waste regulations, covering the entire life cycle of a building. The need for action begins long before the first sod is turned: even at the urban planning level, active attention must be paid to resource conservation when determining zoning and development plans, with the primary focus on preserving and reusing existing buildings in order to avoid new construction and further soil sealing.

When the concrete project planning phase begins, durability and the subsequent reusability of materials must already be anchored in the concept. When dealing with existing building fabric, differentiated measures must then be taken: Renovation takes priority in order to minimize the consumption of material resources and emissions of new “embodied” CO₂. However, if demolition is unavoidable, the principle of direct reuse applies, whereby functional elements such as spiral staircases, doors, or floor coverings are identified and either integrated directly into new buildings or prepared for reuse by specialist companies. Material that cannot be preserved as a whole component must be processed in accordance with the Recycling Building Materials Ordinance – ideally directly on site so that the construction waste can be used immediately for the new building, for example as a concrete additive, thus closing the material cycle locally without significant additional effort.