If we want to build a sustainable future, we may have to revisit what it is we’re actually building things out of. And though the science around the idea is just beginning to emerge, one prime candidate may be using actual living materials like fungus. Or concrete churned out by tiny microbial factories.

Will Srubar, a University of Colorado Boulder materials and engineering researcher, argues in a new The Conversation essay that, living, self-growing, and self-repairing structures may be our best bet to green up the construction industry’s act.

“Living architecture is moving from the realm of science fiction into the laboratory as interdisciplinary teams of researchers turn living cells into microscopic factories,” wrote Srubar, who’s published a number of academic papers on living materials over the last five months. Developing living materials, supposedly, wouldn’t just cut financial costs of repairs and assembly, but also, do away with many of the environmental tolls of manufacturing conventional building materials.

Of course, pivoting to living materials would require a massive paradigm shift, even if scientists figured out how to make these materials both practical and cost-effective. In fact, that might be the hardest part; getting architects and designers to actually consider living materials—as we see with the example of concrete being made from tiny microbes.