Overview of the Study
The study āBeter Benutten Bestaande (Better Use Existing)ā is published by Platform Woonopgave, a Dutch research institute collaborating with the International New Town Institute (INTI) and commissioned by the Ministry of Housing and Spatial Planning. It examines opportunities to split, share, and modestly infill terraced housing built in the 1960ā80 s across the Netherlands, aiming to increase affordable housing, improve sustainability, and support an aging population.
Scope and Potential Housing Gains
Analysis of 2 460 neighbourhoods containing at least 300 postāwar terraced houses reveals a stock of roughly 1.67 million dwellings. The authors estimate that up to 500 000 additional units could be created by sharing or splitting larger homes, while another 60 000ā80 000 could result from modest infill. Overall, the study suggests a potential of around 585 000 extra units, representing more than half of the national target for 2030.
Economic Impact and Costs
Construction costs for full splits range from ā¬150 000 to ā¬180 000 per house, with about oneāthird of the expense attributed to new service installations. Simpler adaptations, such as adding a bathroom or creating a shared entry, cost ā¬17 000āā¬20 000. The report notes that the financial burden can be mitigated through collective financing, shared mortgages, and municipal subsidies, especially when renovations also improve energy performance.
Sustainability and Climate Benefits
The authors stress that reusing existing housing avoids the carbon intensity of new construction, which can be twice as high per square metre. By reducing the need for new builds, the approach helps meet the national carbon budget and supports the EU climate goal of limiting warming to 1.5 Ā°C. Adding green roofs, shared gardens, and modest infill also lowers urban heat island effects and improves stormāwater management.
Demographic Drivers and Care Integration
The study highlights a housing shortage of over 400 000 units, compounded by an ageing population. About 50 % of the terracedāhouse stock is occupied by āemptyānestersā whose homes are larger than needed. Splitting these homes can free space for younger households while allowing older residents to downsize within their own neighbourhoods, reducing longāterm care costs estimated at ā¬24 billion annually for lonelinessārelated services.
Policy Landscape and Barriers
Current Dutch regulations present mixed signals: 16 % of municipalities actively encourage splits, whereas 26 % impose prohibitions. Permitting processes can involve up to three separate applications (building, split, and housingātype permits) and fees exceeding ā¬10 000. The report recommends streamlined procedures, clearer guidelines, and financial incentives to overcome these obstacles.
Technical Options for Housing Adaptation
Two primary methods are described: horizontal division (splitting at floor level) and vertical division (creating separate front and rear units). Horizontal splits are less invasive but may raise acoustic concerns; vertical splits offer better sound isolation but require additional staircases and potentially new entrances. The study also outlines options for infill, such as smallāscale apartment blocks with shared amenities, and emphasizes the importance of maintaining daylight, ventilation, and fire safety standards.
Stakeholder Collaboration and Funding Models
Four financing models are proposed: shared mortgages between coāowners, municipalābacked affordableāhousing schemes, cooperative ownership for infill projects, and neighbourhoodāwide housing associations. These models aim to prevent speculative price increases while ensuring longāterm affordability for both renters and owners.
Expected Societal Benefits
Beyond housing numbers, the authors project increased municipal revenues from higher population density, reduced socialāhousing waiting lists, and lower healthācare expenditures due to improved living conditions. Environmental gains include an estimated ā¬50 000āā¬100 000 annual societal value per hectare of added green space, and a reduction of up to ā¬60 000 per year per senior remaining at home longer.
Implementation Roadmap
The report concludes with a phased strategy: (1) pilot projects in selected neighbourhoods, (2) development of standardized design guidelines, (3) coordination of permit processes across municipalities, and (4) scaling up through publicāprivate partnerships. Continuous monitoring of affordability, energy performance, and social outcomes is recommended to ensure the initiative meets its sustainability and inclusivity goals.