Reusing Timber Formwork in Building Construction: Testing, Redesign, and Socio-Economic Reflection

Abstract

In 2018, the construction sector was responsible for 39% of the worldwide energy and process-related carbon dioxide emissions (Global Alliance for Buildings and Construction et al., 2019). This is partly due to the embodied carbon, which represents the carbon emissions related to building construction and material production (LETI, 2020). While zero energy buildings and zero energy renovations start to get the operational carbon down, the circular economy aims to do this by closing material loops and stimulating the reuse of discarded materials in building construction (Ellen McArthur Foundation et al., 2015). Although it is not a new phenomenon, material reuse does require a substantially different approach and is at this point not yet common in the building industry. This is especially true for load-bearing components. This article presents a pilot project for the reuse of discarded timber formwork for the construction of the façade and (load-bearing) substructure of a new house. Through this pilot case and by reflecting on a series of similar cases, it studies the remaining challenges for material reuse but also proposes and assesses redesign strategies that will allow upscaling the reuse of timber formwork. The project shows that although waste, material, and money can be saved by using reclaimed materials, it does complicate the design and construction process and, as such, does not necessarily reduce the total project budget. Moreover, for reuse to become a current practice, new design approaches and collaborations will need to be established. Finally, socio-economic factors must be considered to increase the acceptance of reclaimed materials in new building construction.

Formwork Engineering for Sustainable Concrete Construction

“…The advantage of plywood is that it can easily be bent to create curved forms and it leaves a smoother finish on the concrete compared to timber. The disadvantage is that it is also prone to water damage and fast decay, limiting the reusability of plywood forms [29]. The quality and cost of different plywood materials varies, and high-quality, water-resistant types are available, but more expensive [5].…”

“…Steel and aluminium formwork can be reused many times due to their durability, and can be recycled at the end of their life [140]. Timber formwork may also be reused if properly cared for and can also be repurposed or recycled at the end of its life as shown in Figure 3 [29]. Plastic formwork can be recycled, although the feasibility of this depends on the type of plastic used and local recycling facilities [141].…”

“…The cost of formwork materials can vary widely depending on the type of formwork system used. Traditional timber formwork is generally the cheapest material option, but it has a limited lifespan and can only be reused a few times before its quality degrades [5,29]. On the other hand, metal formwork systems, such as steel or aluminium, have a higher upfront cost but offer a longer lifespan and higher reusability, leading to lower costs in the long run [31,36].…”

“…The ability to reuse and recycle formwork materials can significantly impact the overall formwork cost [5,29,153]. Reusable formwork systems, such as modular or system formwork, may have a higher initial cost but can result in lower costs per use if reused many times [26,95].…”

Challenges of Energy Renovation

“…7. Pronk et al (2022): Experiences with a house construction (in the Netherlands) by reusing demolition building materials were enriched with other project results, added with socio-economic motivation insights. 8.…”