Single- and two-family homes represent the most popular housing type in Germany. According to prognoses, they will also remain an integral part of new construction activity in future. At the same time, ecologists and urban planners criticize the weak point of this typology including fragmentation of the landscape and high land use along with land sealing. However, other studies also show the potential of single- and two-family homes. For example, home gardens can contribute to the maintenance of biodiversity and improve habitat connectivity if designed appropriately. Based on the Cradle to Cradle (C2C) principle, this thesis analyses the potential of single- and two-family homes. The aim is to analyse the feasibility of a positive footprint according to C2C.
Single- and two-family homes in prefabricated timber construction are chosen as object of reflection. The contractual position of the prefabricated house manufacturers as general contractor and their internal development departments provide an ideal basis for the realisation of a holistic positive footprint. Additionally, the share of prefabricated homes among permitted single- and two-family homes steadily increased during the last years and amounted to 21 per cent in 2019. The largest part thereof is allocated to wooden constructions.
Furthermore, the thesis examines if the elevation of the goals of sustainable construction can lead to C2C buildings. In addition, the thesis discusses if legal incentives can lead to a change of consciousness of the involved stakeholders – away from the minimization of negative effects in the sense of eco-efficiency towards a positive footprint in the sense of eco-effectiveness.
The analysis of the connection between sustainable construction and C2C in the built environment is based on a comparison of different C2C guidelines and the C2C product certification and sustainability assessment methods for small residential buildings. As with the question of a positive footprint the focus lies on the topics of recyclable materials, deconstruction potential, indoor air quality, water cycles, use of renewable energies and promotion of biodiversity. The feasibility of a positive footprint is analysed with the help of case studies. These include C2C inspired single-family homes as well as single- and two-family homes certified according to the
Sustainable Evaluation System for small residential buildings (BNK). For an in-depth analysis of the material related topics (recyclable materials and deconstruction potential), the dismantling of a single-family home in prefabricated timber construction as well as the relocation of a two-family home in prefabricated timber construction are accompanied and evaluated. The analysis is completed by the disassembly of an exterior wall element in timber panel construction.