Roman Streit won an ETH-medal in 2020

Nonetheless, a clear growth in newly built-up areas continues to take place. This contradicts a consistent implementation of the spatial planning strategy for inward development, which stipulates that housing development should mainly be steered towards pre-existing built-up areas. Parallel, in many cases, continuing high demand in and around cities with good public transport connections leads to rising living costs and the considerable under-supply of inexpensive housing. At the same time, various spatial planning instruments are intended to direct the greater part of future population and workplace growth towards urban and suburban areas.

Within this field of tension, non-profit housing developers are highly relevant, as they set rental prices based directly on costs arising from the construction, maintenance and renovation of their properties. They therefore offer considerably cheaper housing than profit-orientated housing organisations, especially in the longer term. However, the significance of the nonprofit housing sector goes beyond the aspect of affordability. Particularly important links are to be found – according to the hypothesis – with the strategy of inward development. These have been studied via the formulation of a Swiss-wide spatial overview of existing non-profit housing projects, as well as the appraisal of their inward development potential. The most important insights from this are:

• In Switzerland, around one in every 20 dwellings is owned by a non-profit housing developer. Non-profit housing is largely concentrated in urban locations, and generally has good to excellent public transport access. In many cases, such housing developments are closely clustered together and characterised by older buildings, thus leading towards further development that is district-orientated, and that extends beyond individual allotments. Overall, from a spatial planning perspective, such properties are therefore eminently suitable for future increases in construction and user density.
• At the same time, the densification of existing properties brings its own challenges: on the one hand, not all non-profit housing is suitable for further structural development – particularly in the case of heritage-listed sites. On the other hand, certain basic parameters critical for future-orientated further development of existing properties are not yet universally in place. Alongside scarcely influenceable circumstances such as the underlying demand situation, these parameters also include factors relating to organisational structures and the housing subsidy scheme. Thus, some organisations lack the resources and expertise for the strategic further development of their property holdings, and the growth incentives in housing subsidy measures on the part of the public sector are sometimes too weakly defined.
• In light of population forecasts alone, the estimate of floor area reserves shows that the current non-profit market share of 4% to 6% of housing stock in Switzerland can barely be maintained by concentrating pre-existing built-up areas alone – even if housing reserves were to be mobilised more quickly, and the legally permissible density partially increased. Greater involvement of the non-profit sector in other inward development options, such as the conversion of brownfield sites or new construction on undeveloped areas, is required to stabilise the market share.
• Statistics on pre-existing stock, as well as on newer non-profit housing development projects, demonstrate the capacity of the non-profit sector to use land in a more resourceefficient manner. Residents occupy considerably less living space on average in comparison with other rented or owned residences, where specifications regarding minimum occupancy play an important part. The implementation of densification measures already taken for non-profit housing stock also demonstrates – above all in the city of Zurich – the significant contribution this residential building sector has made to the application of inward development, in which additional factors, including the acceptance of increased density, as well as guaranteeing quality with regard to design-based, ecological and social aspects, are of crucial importance.
• The affordability of the housing supply as well as, in many cases, the extent to which developers' decision-making structures are democratically designed, are identified as important elements to promote acceptance with regard to densification measures in nonprofit housing. The latter can contribute to assuring the quality of building activities.
• On the basis of selected areas in the cities of Thun and Biel, it has been shown that informal, simultaneous procedures can provide crucial stimuli for the further development of non-profit settlements. The test-planning process represents a proven format for such procedures, which is also suitable for the further development of housing stock in key regions. Complementary participative elements may provide broader social support for the process. Particular attention should be paid to the initiation phase for such processes.
• Besides the implementation of customised planning procedures, a close culture of cooperation between the authorities and non-profit housing developers, as well as a more targeted setting of incentives in housing subsidy measures, represent starting points for the greater activation of potential in housing stock. Through a more consistent coupling of planning interventions with land policy measures – such as the legal or contractual specification of minimum shares for non-profit housing stocks in zone planning, zone expansion and rezoning, or the active land policy of the public sector – inward development also opens up leeway to effectively support the non-profit sector in the advance of new development potential in the future, in addition to underpinning the densification of housing stock.

Overall, this work clarifies the contribution and potential of non-profit housing in the implementation of inward development, whereby quantitative as well as qualitative aspects are relevant. These aspects are to be taken into account in the evaluation of the economic effects of housing subsidies. In future, spatial planning can play a key role in the more resolute utilisation of this potential.