Picture caption: Corn harvest: the bioplastic used is derived from corn residue

US researchers have 3D-printed a natural-material floor panel in one single piece, that appears to be strong enough to replace more carbon-intensive materials such as steel. The biologically-based panel was produced by teams at the US Department of Energy’s Oak Ridge National Laboratory (ORNL) and at the University of Maine.

With steel accounting for 7-8% of global carbon emissions, it makes sense to prioritise the development of alternatives. The floor panel is designed to work well in multi-storey buildings, where steel and concrete would usually be used. It’s much quicker to manufacture than those elements.

The SM2ART Nfloor cassette panel was created as part of the SM2ART program – the Sustainable Materials & Manufacturing Alliance for Renewable Technologies.

It’s made from polylactic acid (PLA), a bioplastic derived from corn residue. This is then mixed with wood flour, which is a waste material from lumber processing.

As well as being less resource intensive, the fact that the floor sections are modular and able to be produced at an offsite factory makes them a cost-effective option for urban apartment blocks and similar residential buildings.

Researchers used a large-scale 3D printer to create a precise, geometric shape, layer by layer. The process currently takes around 30 hours, with the printer working autonomously.

As one of the ORNL researchers, Katie Copenhaver says, this is a big step forward in making the most of organic materials in building projects. As she puts it, “By utilising bio-based, large-scale 3D printing, we replaced assembly made from 31 parts and three materials with a single-material floor panel that is ecologically friendly, and with the same strength as traditional steel floor fabrication”.

Not only is the panel more eco-friendly, but it’s an improvement on the steel alternative. Scott Tomlinson, structural engineer at the University of Maine’s Advanced Structures and Composites Center says, “This single-piece floor assembly is stiffer and provides an improved walking experience when compared to the steel-concrete assembly it replaces.”

This is a vital point, because developers will only choose the more eco-friendly option if it’s as good as, or better than, the original solution. It’s not only about it being more budget friendly, although that’s important too.

Another advantage to 3D printing is that it cuts down on labour. Instead of workers needing to cut channels for electrics, plumbing and heating or ventilation, the floor cassette can be printed with the cutouts already in place.

The phrase “game changer” is overused, but it’s clear that this panel is something of a game changer when it comes to its eco credentials. On top of that, the panel is fully recyclable, so it won’t end up in landfill if the building it’s used in is demolished in the future.

Another advantage I see is that plastic is much lighter than steel, so you’re reducing your deadload by at least half, if not two thirds. This means you can use smaller, lighter steel beams and reduce your carbon footprint further.

The Nfloor panel is in the initial stages of development, and there are plans for further research on flame retardants and sustainable insulation. The teams involved also want to make the manufacturing process even more efficient.

Isolating one individual component of a building and researching a better, more eco-friendly alternative is a great way to gradually transform the industry. We won’t get fully sustainable buildings overnight – these still tend to be flagship projects rather than the norm – but every step towards sustainability and a full circular economy is a good one.

What do you think? And what do you see happening? Are your clients asking for more eco-friendly options, or does everything come back to cost?

Meanwhile, if you need any assistance with the structural elements of an upcoming project, please do get in touch.