we need to build regenerative or restorative
buildings, ones that give back to the
env i ronment , the o c cupant s and
community more than they take. Green
roofs and walls are an important and
growing component of restorative
buildings. Since we started collecting
statistics, which was in 2004, we have
completed an annual market survey of our
members. We estimate that we built a
hundred million square feet of green roofs
in North America in ten years, since 2004.
Now the value of those green roofs probably
ranges anywhere from fifteen to thirty
dollars per square foot, depending on the
type of roof, the depth, and a whole bunch
of factors that are too complicated to get
into, but there's a range. It's not like a light
bulb that has a certain cost – the cost varies
depending on certain markets and
situations, whether it's a retrofit – there's a
whole bunch of factors that affect cost, but
just say from $15-30 per square foot. By
2022, our goal is to put a billion square feet
– an additional billion on the roofs of
August-September 2014
| BusinessWorld | 43
