The French Parliament recently approved a new law requiring all new commercial buildings to partially have their roofs covered with plants or solar panels. The new requirement will apply to all new buildings in commercial zones. Initially, the proposal posed by French environmental activists was for the roofs to be completely covered by greenery.
The new law adds costs for both building owners and developers, so the government decided to ease up a bit on the cost by allowing for the roofs to be partially covered instead of fully covered.
Here in the US, the Environmental Protection Agency listed some key benefits of having plants on the roof. The EPA pointed out that green roofs have been proven to reduce “heat islands” by providing shade, removing heat from the air, and even reducing the temperatures of the roof surface.
“Green roof temperatures can be 30–40°F lower than those of conventional roofs and can reduce city-wide ambient temperatures by up to 5°F. In addition, green roofs can reduce building energy use by 0.7% compared to conventional roofs, reducing peak electricity demand and leading to an annual savings of $0.23 per square foot of the roof’s surface. These temperature reductions and energy efficiency benefits are a key contributor to the growing popularity of green roofs in the United States.”
The EPA even shared different types of green roofs, noting that for extensive ones, very little maintenance is needed once it’s set up.
We all know that, eventually, rooftop solar panels pay for themselves and start making the owner money. An idea that crossed my mind is that perhaps solar installers could give an option for a fully covered roof as an upsell — solar panels plus a green roof.
If I owned my own home, I would definitely consider getting a green roof. I think France is on the right track, and hopefully we’ll see more nations embracing better laws regarding commercial and residential roofs.