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Collateral Spaces
This NWO-funded project introduces the concept of collateral space to describe how housing is conceived not only as homes but also as assets that back debt. It redefines residential landscapes by showing how large-scale mortgage schemes shaped architectural forms, layouts, and urban expansion. Focusing on Amsterdam’s postwar expansion neighbourhoods, the project links building permits with mortgage registrations in a digital database, enabling systematic analysis of which spatial elements were registered as collateral. By tracing how financial logics co-produced space, the project highlights the historical roots of asset-based housing, revealing connections between postwar planning, mortgage finance, and the long-term reproduction of housing inequalities.
ABOUT
Histories of Amsterdam’s postwar expansion have mostly read its new neighbourhoods through modernist design and welfare-state ideals. Less attention has gone to the mortgage credit that paid for many of these homes, and to how it shaped their standard plans, typologies and materials. This project looks at that gap in three districts: Slotermeer and Slotervaart in Nieuw-West, and Buitenveldert in Zuid. It tests two ideas. The first is that private housing was structurally shaped by mortgage finance, so that its forms, layouts and construction followed the need to make each dwelling reliable collateral in case of default. The second is that these projects were spatial forms of an emerging asset-based economy as much as expressions of modernism and welfare. With housing affordability, financialisation and inequality at the centre of today’s debates, the origins of asset-based homeownership deserve a closer look.
METHODOLOGY
The project starts from the mortgage rather than the building. Most studies of postwar housing begin with the architect’s drawing and work outwards to policy and ideology. Here the entry point is the mortgage registration: the legal record in which a house was described, valued and pledged as security for a loan. Only then does the research turn to the permits and plans, asking how the house the lender registered compares with the house the architect designed. Reading the two archives against each other makes the financial life of a dwelling visible. The result is one database in which architectural features and mortgage conditions can be compared house by house and neighbourhood by neighbourhood.
WORFLOW
1. Start with the mortgages
Mortgage registrations for owner-occupied dwellings in Slotermeer, Slotervaart and Buitenveldert between 1953 and 1965 are collected from the Kadaster. Each deed is read for what it describes as security: the parcel, the building, and any fittings, extensions or outbuildings named alongside them. The deeds also record the loan sum, the lender, the repayment terms and what happens in case of default.
3. Build Database
Both sets of records are transcribed, cleaned and structured in a relational database, with separate tables for parcels, dwellings, permits, deeds and lenders. Keeping them apart but linked means the same house can be queried from the financial side or the architectural side.
5. Compare across the city
The results are set side by side across the three districts and across the period, to see whether collateral logic varied with location, housing type or the timing of construction, and how it relates to the wider history of homeownership in the Netherlands.
2. Trace each mortgage to its permit and plan
Using the parcel number and address, every registration is matched to the building permit and architectural drawings held by the Amsterdam City Archives. This shows what was actually designed and approved for the same property: its typology, floor area, layout, materials and construction method.
4. Analyse form against finance
Text mining of deeds and permits picks out recurring terms, clauses and descriptions of pledged property. GIS mapping places each registration on the historical parcel map. Statistical modelling tests whether particular lenders, loan terms or dwelling types go together, and digital reconstruction of selected plans shows how the registered collateral sits within the built house.
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