Reusing waste wood for an exterior wall element

Abstract

In 2017, 1610 million kg of waste wood was collected in the Netherlands. The building and demolition industry was, and still is, the most significant contributor. The estimation is made that in 2017 23% of this wood, 370 million kg, consisted of solid waste wood. This solid waste wood has the potential to be reused as a building material without having to shred it. The current commonly used timber frame construction methods in the Netherlands are not suitable for construction with waste wood. Waste wood has certain characteristics that differ from regular wood for construction on a larger scale. It is possible to create an exterior wall element from waste wood, but this is a time-consuming process. Manual labor is expensive in the Netherlands. Therefore, it will probably not be an economically feasible solution to construct the wall element. A carpenter that needs to modify every piece by hand to get everything in the correct dimensions will probably be more expensive than buying new wood. Using digital fabrication combined with a parametric model can offer a solution to the challenges of constructing an exterior wall element with waste wood. The characteristics of the waste wood are obtained and digitally stored in a database. This database can communicate with a parametric model and generate all the separate 3dm files required for digital manufacturing. The final design was made parametric so that it could communicate with the database. Using Rhino, Grasshopper and Python, a prototype of the exterior wall element tool was made that bridged the parametric model with a waste wood database and gave the user some insight into the waste wood statistics of the design. Python scripts were used for an efficient selection procedure whereby additional material waste could be minimized in the exterior wall element. With the exterior wall element tool, it is possible to create a national database with waste wood. The sellers of waste wood can be the demolishing companies but also the waste wood processors. A contractor can use the exterior wall element tool online to create an exterior wall element from waste wood. Here the user, in this case the contractor, gives the desired dimensions of the wall, and the tool generates a design of an exterior wall element. Additional information is given about the cost, the amount of wood required and where the wood is located. The contractor can adjust the parameters of the model and choose, for example, the cheapest option or the option where all the wood is closest to the building side. In the end the tool generates a list with 3dm files for every piece of wood that has to be modified. These 3dm files can be used for digital fabrication.