3D Printed Buildings - A sustainable future, or a modern gimmick?

There is no shortage of news about 3D printed buildings, while originally big news in the built environment industry, their creation now rarely makes the headlines. But while the development of this new technology has continued around the world over the past decade, the question should be asked about what role it will play in the future. 

While the specific methods differ, there are a few comminalities shared by 3D printed buildings. The first is the method of 3D printing. The technology has existed at a small scale for decades, and can generally be divided into three categories. The first category is FDM, or fused deposition modelling, where a printer head sets down material in layers, relying on gravity and the melting/fusing of materials to hold the structure together. The second is resin printing, where a liquid resin is hardened using targeted UV light, allowing for much more precise modelling, and more organic forms. The third is laser sintering, which uses a metallic powder and a high powered laser to superheat the metallic powder together, allowing for 3D printed metal forms. 

In the built environment, all 3D printing has been based on FDM technology, and while this is by far the easiest to upscale to building-sizes, it also has a number of key faults which pose limitations on the building fabrication. Firstly, the structural integrity relies on fast-drying and fast-fusing materials. Long overhangs or cantilevered elements would need separate formwork to support, or else risk the collapse of the material. This limits the form of buildings, the speed the printer can move, and also the types of material which are suitable to be printed with. 

Secondly, the layered structure of FDM printing is unfortunately a great weakness. For example, a 3D printed concrete wall compared to a solid in-situ concrete wall would be noticably weaker, with an uneven surface. Not only does this pose structural limitations, but the irregular wall surface requires additional work to smooth and finish. Inevitably there is also the creation of air-bubbles and dust entrapment within the material, sealed between layers during the printing process. This poses issues for hygiene and air-tightness of the final building, while also creating weakpoints within the structure that are hard to predict and account for. 

Thirdly, the materials that can be 3D printed at this point in time are highly restricted, with most opting for a concrete mix, designed to dry quickly and not fall apart during the printing process. This limits the design of the building, while also meaning that thin walls or detailed elements are extremely difficult to print, with a high risk of failure. 

However, despite these weaknesses, there are some great advantages of 3D printing. Firstly, the automated nature of 3D printing allows for 24hr construction, with minimal manpower during the process. Not only is this extremely quick, but also significantly cheaper than traditional construction methods. Secondly, the 3D printer head can be mounted to frames of various sizes, allowing for a great range of printing scales, and also for the creation of organic and highly curved forms that would be challenging and expensive using traditional construction methods. 

In conclusion, 3D printed buildings are still in their early stages, and while they have numerous drawbacks, and are certainly not the miracle solution to future construction that some may imply, it is a promising technology with a lot of potential. It will be fascinating to follow the development of 3D printed buildings, and see how they address the endemic challenges of FDM printing, or whether a new printing method is developed specifically for the built environment.