Recently, the first BPD homes with a material passport were completed: 94 owner-occupied dwellings and 33 rented social housing units in Buitenoord, the new sustainable housing district in the Dutch town of Wageningen. This district is characterised by innovative use of energy and materials, which has been implemented in all of the homes, some of which are also energy-neutral. A fine example of circular area development — but what exactly is circular area development all about? What is the added value of a material passport? We talked about this with Arjen Kleijer (Location Manager BPD), Annelies Barnard (Director of Woningstichting), Anja and Maarten van Osch (homeowners in Buitenoord) and Patrick den Boer (BIM Director at Trebbe Wonen).
What is BPD’s perspective on circular area development?According to Arjen Kleijer, the focus on reuse is particularly important. ‘We can reduce waste streams by using natural, recycled and reusable materials. In this way, we are also creating closed-loop cycles of raw materials on various scales (i.e. districts, municipalities, regions and national). Material passports help us to make conscious choices about materials, so that we are able to apply as many high-quality recycled resources as possible and to design buildings in a way that enables future, high-quality reuse and reassemblage of materials.’
Buitenoord is a residential area that breathes sustainability. Why does this area stand out so much, in terms of sustainability?‘Since 2011, the entire district has been developed to be natural gas-free — which was long before this became the norm in the Netherlands — and the new homes’ indoor temperature is regulated via soil energy. The residential district has truly had a pioneering function and its sustainable ambitions are still high today. This can be seen in the energy facilities inside the houses, as well as in the layout of the entire district. Central issues include climate adaptation, circularity, energy transition and health. In this way, we are developing living environments that are increasingly nature-inclusive’, says Kleijer.
What is the role of material passports in the completion of each of these properties?According to Patrick den Boer (BIM Director at Trebbe Wonen), the main difference is that more data need to be recorded, compared with conventional properties. However, this is not the main issue, seeing that the 3D data models are already of good quality. So, what is it then? Den Boer answers: ‘Initially, the effort was mainly focused on creating models that were building-specific. However, it is now possible to distinguish individual building numbers/house numbers in the 3D models. The link to and management of the database still requires some time. Fortunately, the concept allows us to benefit from this in every project. The individual passports for the home buyers are initially created under our account and digitally transferred to BPD before completion of the homes.’ Registration and documentation are the first steps, according to Kleijer: ‘All materials in the currently completed 127 newly built homes in Buitenoord are now registered on the Madaster Platform. The next step is to give the homeowners insight into the material, circular and financial value of their home on the basis of the materials passport. We also want to offer owners the possibility of keeping their material passport up to date.’ Kleijer says that BPD is now also able to go one step further: ‘Because the passport clearly shows all the materials contained in a building, it will be easier to apply more sustainable and, where possible, bio-based materials.’
What would be the added value to housing associations of having a rental housing stock that is equipped with material passports?According to Annelies Barnard (Director/administrator of Woningstichting), material passports are an important tool in realising sustainable ambitions. Barnard explains: ‘Our goal is for our stock to be carbon-neutral by 2050. That is why we want to make our homes more sustainable and climate-proof, taking housing expenses as the starting point. It goes without saying that we want to do it right the first time, when it comes to new buildings. We also link the increase in sustainability to planned maintenance. Material passports increase the insight we have and enables us to also work towards our CO2 reduction targets. Lessons learned today can be applied in our future efforts to use more sustainable materials. After all, measurements are the key to knowledge!
To what extent does sustainability play a role in rental housing?Barnard states that, in Wageningen, sustainability is high on the agenda of many of the parties involved: ‘Themes such as climate adaptation and circularity are not only important for policymakers at the Woningstichting and the municipality, but for the tenants as well, who also consider a sustainable home to be important. In addition to the sustainable facilities, they also look at what it offers them in terms of comfort, ease of use and affordable housing costs.’
Are home buyers also more interested in sustainable housing?Sustainability plays an important role, if we are to believe Anja and Maarten van Osch (homeowners in Buitenoord). They bought a sustainable home that is well insulated and natural gas-free, has a heat pump and is virtually energy-neutral through the use of solar panels. Anja van Osch explains: ‘We consciously chose a new-build house with sustainable specifications. Apart from the financial advantages (low costs) and convenience (underfloor heating/cooling and low maintenance in the first years after purchase), we find it very important that our household has a low impact on the environment. The material passport gives us a good insight into this. Knowing the material, circular and financial value of our home is not only fun but can also be very interesting for renovation or valuation in the future.’
Will the completion of homes with a material passport become the standard?According to Kleijer, we are currently undergoing a learning process: ‘We see that more and more builders and suppliers and producers of materials are aware of the need for a circular approach to area development. On top of that, the national government intends to make material passports compulsory. It is, therefore, to be expected to become the standard. What is good to see is that the documenting of materials used is becoming more commonplace.’
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