MIT Develops 3D-printed Floor Trusses from Recycled Plastics

MIT researchers are exploring how recycled plastics can be used in construction by 3D printing structural elements such as floor trusses. The approach combines additive manufacturing with polymer composites to create lightweight, load-bearing components that could help address both plastic waste and the global demand for housing.

Engineers at MIT have developed a 3D-printed floor truss system made from recycled plastic, demonstrating the potential of polymer-based construction materials. The concept aims to give single-use plastics, such as bottles and packaging, a second life as structural components in buildings.

Using large-scale additive manufacturing, the team printed trusses that can be assembled into a conventional floor system. The elements are designed to be lighter, modular and easier to transport than traditional wood-based structures.

The researchers tested the printed system under increasing loads. The result: the structure withstood more than 4,000 pounds, exceeding key requirements set by U.S. building standards.

Each truss weighs around 13 pounds and can be produced in approximately 13 minutes, highlighting the efficiency of large-format 3D printing. The design also optimises the stiffness-to-weight ratio, ensuring structural stability with minimal material use.

The trusses were produced using a composite material made from recycled PET and glass fibres, improving both durability and printability. The long-term goal is to process "dirty" plastic waste directly, without extensive cleaning or preprocessing.

The MIT HAUS research group is working towards integrating shredding, pelletising and printing into decentralised production systems. These could enable local manufacturing of building components using regionally available plastic waste.

Beyond floor trusses, the researchers aim to print additional structural elements such as wall studs, roof trusses and foundations, enabling the construction of entire building frames.

The approach could contribute to circular economy models in construction, reducing dependence on timber while addressing plastic waste streams. It may also support scalable solutions for global housing demand, particularly in regions with limited access to traditional building materials.