The Roof is on Fire! Potential Risks of Green Roofs
This past weekend I had the opportunity to have an excellent conversation with Chris Cheatham of GBLU and Shari Shapiro of GBLB regarding green roofs. The conversation was started by Shari when she posted an article addressing green roofs and their risk for fire potential. Brian Phelps provided an excellent paper addressing green roofs in general and highlighted a section of the paper addressing the fire potential of green roofs which rebuts the article posted by Shari.
While I had previously considered the potential problems with green roofs such as leaks, collapse, and corrosion I had never contemplated a green roof as a potential fire hazard. I suppose part of my failure to consider the risk of a fire potential with a green roof is the key phrase "green" as in properly irrigated and not likely to ignite. However, imagine a green roof gone dry, particularly a green roof which is accessible by building occupants. A dry "green" roof, a stray cigarette, and a urban brush fire! Possible, but highly unlikely. In fact the evidence presented in Christine Robertson's paper suggests that in Germany where green roofs are extensively used there has never been a green roof fire and that as a result green roofs are associated with a 10-20% discounted rate on fire insurance. Likewise, Ms. Robertson's paper suggests that the threat of fire
is 15-20 times higher on bare roofs with fully adhered bituminous waterproofing membranes
than on extensive green roofs with grasses, perennials and sedums.
Keep tuned to Konstructr for the input of Mark Rabkin a knowledgeable insurance guru and risk management profession who will be chiming in with green roofs from an insurance perspective in the near future.
