President’s Message
By Marc Jamieson, President, OIRCA

Green Roofing Systems and the Building Code

 I recently read an article authored by Mr. Mark Graham, the Associate Executive Director of Technical Services for the National Roofing Contractors Association (NRCA) in the US regarding code compliance for green roofing systems.  He notes that although the popularity of these systems is increasing, their conformity with building code requirements is a concern, particularly regarding resistance to exterior fire exposure and wind uplift.

In Canada, the current version of the National Building Code (NBC) and the recently released Ontario Building Code (OBC) do not specifically address these types of systems.  While it would seem that there are no prescriptive requirements for green systems, it would appear that their use is also not restricted.

Other standards agencies that impact roofing design and application such as Factory Mutual (FM Global) and Underwriters Laboratories of Canada (UL) have only just started to address garden roofs.  Back in January of this year FM released Property Loss Prevention Data Sheet 1-35, which provides general guidelines for designing these systems within the FM system but clearly states, “there currently are no complete green roof assemblies that are FM approved”.

UL is similarly slow in developing and conducting tests for roofing systems covered with growing medium.  Others that promote the virtues of these systems, manufacturers for example, do little to provide information to designers and installers about whether the roof systems comply with Canadian or provincial building codes.

The demand for sustainable design and energy efficiency has certainly pushed the envelope especially when it comes to LEED compliance.  Desperate to build points within that program, owners and designers select green roofing systems matter-of-factly.  Never mind whether the system meets code compliance or for that matter will perform as well as a conventional roofing system.

Motivation to go green seems to vary from project to project and from owner to owner.  The City of Toronto certainly has taken a strong position with their Toronto Green Development Standard and goal of “making a sustainable city happen”.  So much so that the city’s executive committee recently gave the approval to spend an additional $3.2 million dollars for a green roof on the newly refurbished Victoria Park subway station.  That decision, in the face of Toronto’s financial crisis, coincided with a cutting of hours for libraries and community centers along with some consideration to shutting down certain bus routes.

From a purely technical aspect it is timely to reflect back on the summer of 2007.  Near drought conditions in Toronto for example have certainly taken its toll on my lawn never mind the green or should I call them brown roofs in this city.  How environmentally sound is pumping hundreds or thousands of gallons of water to “sustain” ones lawn or green roof?  I suspect that most green roofs do not in fact have irrigation systems which means that they will dry out under these conditions and that surely posses a threat of “spread of fire” over a roofing system not to mention the potential for wind erosion that may occur jeopardizing a system’s ability to stay in place.

As roofing contractors we generally install roofing systems that have been designed by others.  That being said we do have a responsibility to ensure that the roofing systems we build are viable, legal and in the best interests of the owner.  The principles of sustainable building and roofing design are truly honorable.  We should never lose sight of the fact that a roof is one of the most important components of the building envelope and the philosophy of “green” while laudable must never get in the way of sound roofing design and application.

It has been stated before in this publication that as roofing contractors we are in the labour business and are quite prepared to tender any and all roofing projects.  We are also not adverse to repairing or replacing green roofs sometime down the road.  But when that day comes, rest assured that the cost to the owner will be substantial.  I caution everyone connected to sustainable design to consider that fact and to do your homework when it comes to code compliance, certification and the specifying of garden roofing systems.