Has Canada Figured Out Green Roof Insurance, Eh?
A few weeks ago, Toronto announced a mandatory green roof requirement, which my fellow bloggers dutifully covered. When I read about the green roof mandate, I thought of another Canadian city with a similar program.
You remember the Vancouver Catch-22, right?
Many British Columbia jurisdictions, including Vancouver, began mandating green roofs. Simultaneously, the Homeowner Protection Office required homeowner's insurance covering roofs for new developments. A resourceful government official with the Homeowner Protection Office did some digging and sent out a letter emphasizing that insurers would not issue policies covering green roofs.
In the end, the Homeowner Protection Office had to call a meeting with the insurers, the building industry and government officials to find a solution. Quite embarrassing.
When I read about the Toronto green roof mandate, I thought to myself "good for Toronto, they ironed out all of the insurance and liability issues associated with green roofs."
Marks says, however, that green roofs built to the Toronto construction standard won’t be able to pass Underwriters Laboratories of Canada’s CAN/ULC S107-03, Methods of Fire Tests of Roof Coverings. “Under the flame-spread test, they shoot a flame across the top of a traditional roofing membrane,” says Marks. “There isn’t one green roof that will pass that test — the vegetation will burn, and the City of Toronto has been aware of this.”
Marks notes that the insurance sector is generally reactive to emerging issues, not proactive.
“The insurance industry hasn’t caught up with this yet,” he says. “They may need to experience some losses and claims before clueing in.”
I am no engineer but I am pretty sure grass catches on fire if you shoot a flame at it.
The green building industry is a brave new world. How long will it be before the insurance industry can assess the risks associated with green roofs and projects?
Photo: Earth Hour Global
Green roofing consultants should simply do what lighting manufacturers do every time they innovate...get UL approved. It's a cost of doing business.
I'm no engineer either, but the whole concern about grass fires on green roofs has seemed a little overblown. While I know that grass burns, it usually doesn't make for a very hot or long fire. Unless there is some other large source of combustible material also stored on the roof which would also catch fire (which would itself be a separate and greater issue of concern), the alarm by the insurance companies seems a little dramatic.
With that background, it was very interesting to click through to your linked articles. In conjunction with the article from which you quote, the Daily Commercial News is also running a poll asking whether its readers are concerned about green-roof fires. Presently, the majority of respondents are not. What is more interesting, however, is the comment to the poll left by Zach Williams, CCM Roof Garden Manager, Carlisle SynTec. He discusses the likelihood of green-roof fires, and the likely outcome. His experience, both theoretically and from experience, rings true. Mr. Williams writes:
Someone threw a lit cigarette off a balcony onto the roof garden below which was vegetated with tall and dry native grasses. Within a few minutes a fire broke out and began to envelope the roof. Once the fire department arrived, it had all but burned itself out. No damage to the roof occurred and remediation simply involved replanting. Even in the worst case scenario of dry grass, damage is inherently limited since the grass does not have a large amount of energy, even with a high surface to air ratio which encourages fast burn times.
I agree with Andrew Falk. Green roofs have a decades-long history in Germany and fire has not been a problem. Over there, they are considered fire-resistant if built in accordance with FLL guidelines (also available in English). Green roof growing medium is predominately mineral (as opposed to organic) content, so not very flammable. On a properly designed and installed green roof, the membrane is not exposed, rather it is protected by the growing medium, other parts of the assembly, and plants.
Tall grasses are not used on many functional green roofs, which are usually too thin to support that kind of root system. Hardy succulent plants are much more common, they have a high water content and would seem to pose even less fire risk than that described above.
I have been researching a book on green roofs for over a year and I have not heard of any significant fires (and I have tried to find them). Using available guidelines (and common sense) should keep such risks to a minimum.
@James Bedell - You are going to have to explain to me what "UL approved" means. Got any good links?
@Andrew Falk - Thanks for pointing out the comment. I had missed that. In retrospect (and I didn't fully develop this thought in the post) I would add that the most interesting part of the Daily Commerce article, to me, is that there may be current regulations in place that have to be modified to work with new green building strategies, like green roofs.
@Linda McIntyre - Thanks for your comment. I know you have been diligently researching your book, so if you have not heard of a significant green roof fire, I am going to take your word for it. I look forward to meeting you in August!
If someone in the insurance industry has a problem with Green Roofs, they should focus their efforts on the effects of water infiltration from poor membrane installation or design. Adding a green roof requires additional care and concern within structural engineering to prevent water infiltration leading to mold and moisture problems. Until the spores start showing up, however, mold isn't as sexy as a good old fashioned fire.
I absolutely agree with Mark. The issue of proper design and installation of the membrane to prevent water damage seems of much greater concern to me with these systems.
I would like to draw your attention to the following -
Green roofs protect buildings against fire. An investigation in Berlin into the resistance of green roofs to fire found that green roofs are more resistant than gravel roofs and that the succulent plants used in green roofs offer good fire resistance (Köhler,2004)
The “film bunker� at the UFA studios in Babelsberg was used in the 1930’s to store valuable film material such as the original Marlene Dietrich movies. The rooms were separated by thick brick walls and the roof was greened for added fire protection (Köhler, 2003)
and the following You Tube green roof fire test -
http://www.youtube.com/watch?v=fee_jsP1w6I
Andrew Clements.
The Greek Green Roof Association.