When most people offer guests a tour of their home, they give you a spin through the kitchen, living room and maybe their yard. At Mark and Lucia Freeman’s home, an elegant mid-century modern residence in D.C., you might also get an invitation to climb a ladder and check out the roof. It has become the talk of the neighborhood — and occasionally of social media — since the couple installed an array of native plants up there last year and added a bracing system to keep it all from sliding off.
The pair are architects who try to incorporate eco-friendly features whenever possible, so when they needed to replace their roof, Lucia advocated for a green roof instead of a traditional asphalt or metal surface.
Green roofs are far from a new architectural phenomenon; the Hanging Gardens of Babylon and the turf houses favored by Vikings both provide early examples, and modern European buildings have been incorporating green roofs for decades. But as climate change makes extreme weather more common, green roofs can check off a lot of eco-friendly boxes for homeowners or developers. Still, they are relatively few and far between; there are only a handful in the District.
Their experience aligns with federal research that suggests “green roofs are capable of removing 50% of the annual rainfall volume” that lands on them, according to an Environmental Protection Agency study.
Installation requires placing alternating layers of waterproofing and water-retention membranes, filtration sheets and drainage materials. That is topped with a few inches of substrate and plants, serving as a functional Dagwood sandwich that helps protect the standard roof underneath. Installers often use preselected assortments with low-growing, shallow-rooted plants tailored to the local climate.
In the Freemans’ case, those plants include fragrant chives and nubbly succulent beds; plump mushrooms have also cropped up since they installed the roof.
Now that the vegetation on the Freemans’ roof is noticeable from the road, passing drivers frequently reverse their cars for a second look. When the family works in the yard, they regularly see pedestrians examining the feature. Some linger longer than others, asking detailed questions about what’s going on up there.
Most anyone who does stop by — whether for the Freemans’ regular crawfish boil, a family gathering or just on their way home from work — tends to pose the same question.
“Why would you want this on your roof?”