“A lot of what we’ve done over the last decade has been focused on development, but in the last six months, I’ve gotten so many calls on existing buildings,” said Keitges.

Keitges points out that green roofing is expected to be a $14-billion global business, not only in new construction, but for buildings looking to increase their water management so as not to overwhelm drainage infrastructure when severe storms blow through.

Keitges said the explosion of green roofing is partly due to the COVID-19 pandemic, which caused many buildings to become virtually empty as people work remotely. Now building owners and businesses are seeking ways to bring people back into the office by giving them green spaces to enjoy.

In addition, hospitals and school districts are looking to create green roofs on their buildings to promote mental health and well-being. This is based on the idea of “biophilia,” a hypothesis stating humans have an innate instinct to connect with nature. One study found that there is “solid environmental evidence for the value in biophilic architecture,” including research from 1984 showing increased healing rates in hospitals with views of nature and daylight.

“The data is actually so profound that the medical industry adopted it, and now I hardly doubt you’re going to see a hospital built without using biophilia,” Keiter said.