Advice on the economic and sustainable reuse of building materials in the Netherlands: in order to be able to provide this, TNO has developed BOB (Bouwmaterialen in Beeld). BOB is a database that provides insights into the materials that are used in the built environment of the Netherlands so that they can be reused, such as in circular building projects.

Would you like to know more about the BOB model?

Please contact Mark van Ommen

More circular building

We are being faced with the societal challenge of drastically reducing the burden of construction on our planet. In addition to reducing the use of various materials, extending their lifespans and formulating bio-based solutions, we need to adopt a circular building approach with greater reuse of (raw) materials. However, we do not know with any precision which materials can be found where and whether or not they are suitable for reuse.

Coarse material passport

The BOB model is based on public databases and building profiles developed by TNO: a coarse material ‘passport’ of the built environment of the Netherlands, including the theoretical supply and demand of building materials. For the government in particular, BOB makes the possibilities for reuse transparent through the addition of facts such as quality, residual value, environmental impact and logistical implications. By exchanging data with partners, TNO accelerates the development of precise material passports and generates the insights needed for truly smart reuse.

In collaboration with Madaster, TNO is developing an online library in which materials and buildings are documented, as well as land partitioning and ownership in the land registry. With Madaster, anyone can have a materials passport made for their building(s). In this way, TNO is creating a practical platform for registration and analysis that promote the circular building sector.

Comparing scenarios

In a recent collaboration, the municipality of Assen indicated that it needed a tangible substantiation of its ambition to build in a circular manner. TNO compared three scenarios: flexible ‘zero-on-the-meter’ new buildings, reuse from former industrial areas and the redevelopment of the city centre. The indicators in the BOB model are climate change (CO2 emissions), the Environmental Cost Indicator (ECI) score, inclusive employment, material costs, knowledge development in the region and the value of housing. The result is a useful overview of the pros and cons per scenario and indicator.

Amsterdam Metropolitan Area

In the Amsterdam metropolitan region, TNO and the Economic Institute for Building have carried out a quick-scan regarding the effects of circular building on logistic flows and the use of space. Over the next 20 years, 250,000 homes and a large number of utility buildings will be built there, including the construction, reconstruction and replacement of infrastructure. The quick-scan showed that up to a quarter of this large number of new homes can be built in a circular fashion with used materials.


Ing. Mark van Ommen MBA

Be inspired by TNO Insights about Circular Economy