Once your door, now your coffee table

Within AUAS, the Digital Production Research Group explores how advanced technologies such as computational design and robotic production can contribute to the circular transition. The group is currently working with many project partners on the development of new applications for circular materials, including waste and residual wood. This is the case of Circular Wood for the Neighborhood. ‘In this project, we addressed the technical challenges that are involved in working with waste wood,’ says Project Manager Tony Schoen. ‘How much wood is released from housing renovations, and of what quality? How can you reuse the wood as efficiently as possible? To investigate this, we ideated three application case studies, and developed several physical prototypes.’

What kinds of objects are involved?

Malé-Alemany: ‘The first case study involves a group of individual houses, which is equivalent to a small-scale renovation project. We could be making use of their used doors to make a small piece of furniture, such as a coffee table. The underlying idea is that all the tenants can get their own door back, in the form of a new circular object for their new house, after the renovation. This makes the concept of circularity extremely tangible for tenants. The second case study focuses on a much larger renovation project, in which the harvested wood can be turned into a community structure for all residents. This kind of renovation releases a large amount of wood, which can be returned to the tenants in the form of a valuable object for the public space, such as a small pavilion or playground structure. You could even design and assemble this object together with tenants, as a means to increase their involvement in the neighbourhood. The third case study explores an even larger perspective. That is the collaboration between multiple housing corporations, sharing wood from different projects. These entities can work together to create a shared material bank, which can ensure wood availability at the moment that it is required for other renovations. For this case study, we designed a system of room dividers that can be adapted to any given space, adjusting the height and length of our digital model. This design system takes into account the database of wood available in the material bank.’

What was the role of digital design techniques in creating the three objects?

Schoen: ‘The designs were created digitally, and were used to inform the production using industrial robots. The first step was to enter all the pieces of usable wood in a database. We then started developing a script for design (with the help of algorithms) which has access to the database. You can tell the computer what basic shape you want to get, such as a small table. You can also enter a number of requirements: for example, the object must have legs, be no higher than 50 centimetres and have specific types of joints between the wood pieces. The script will then search the database for the available wood, calculate how it can best position the pieces and come up with a design. In summary, we wrote software that can generate virtual 3D objects and send the production instructions to the robots, to physically produce its various parts in the lab. The robot will make the right notches on every piece of wood, so that all parts fit together precisely. Only the actual assembly of the designed object is done by human hands.'

Which challenges were encountered in this project?

Schoen: ‘It proved difficult to link renovation projects to our research, due to several reasons. Firstly, renovation planning is not set in stone. For instance, one of the projects from which we were supposed to obtain waste wood started much later than intended, so we did not receive the materials on time. Second, we also realised that housing corporations don’t always have information about the availability of wood within their projects. In one case our contact person did not have the correct data. Thus, our research was linked to a project that could not provide any wood. So one of the main lessons we learned from this research is that if we want to reuse wood from these renovations, it is critical that housing corporations have a clear picture of the materials used in their projects. A standard surveying process is therefore required, in order to create an inventory of potential wood coming from renovation projects.’

Malé-Alemany: ‘New housing projects, in which BIM (Building Information Modelling) and explicit material passports are implemented, will make this information available. However, these projects will not be ready for renovation until 50 years from now. This creates two opposite realities. Older homes, made with high-quality wood that is very suitable for reuse, which provide little to no data about the amount and type of materials they contain. And newer homes, where all materials used are well documented and can be forecasted, yet build with much lower quality wood.’

Despite these challenges, can you see a future for the circular reuse of waste wood?

Malé-Alemany: ‘Absolutely! All the partners in the project, including us, can see the possibilities of harvesting wood from housing renovations, to make circular applications powered by digital production. However, to make reuse a success more cooperation with other parties in the value chain is required, because they should share the technological investment in order to achieve the highest quality of reuse. What can they do with the wood? And how can everyone in the chain benefit from this added value? These are the questions we will be investigating in subsequent projects.'

Schoen: ‘We can identify several scenarios for the valuable reuse of waste wood. As we have shown in this project, you can reuse it on a local scale to make products for tenants of renovated houses. Circular use at a local level allows you to create objects with a story that is connected to the source of the material, giving them great added value. The opposite option is to think on a large scale, converting waste wood from many large renovation projects into semi-finished products for the construction industry. In this case, the wood is reclaimed according to a standard method and processed in a large factory, facilitating that it can be reused as a ‘new’ material for all applications within the construction industry or any other wood-related sector. This approach is much easier to apply to large projects than smaller renovations.’

Malé-Alemany: 'At the Robot Lab and Digital Production Research Group, we consciously play a role in both these scenarios, because they both have advantages and don't rule each other out. And certainly for both scenarios, the more you apply digital technologies for intake (3D scanning, metal detection, etc) and pre-processing of waste wood (robotics), the greater the chances that you can reuse this wood efficiently, at the highest value. That is what it is ultimately all about: applying technology towards a more sustainable future.’