Green Roofs - Living Architecture Monitor - Fall 2012 - (Page 6)

ON THE ROOF WITH… “communication is key. the cLient shouLd Be aBLe to communicate With the designer and contractor as to What they Want the rooF to do For them” angie durhman to HVAC systems, removal of plant material from birds, and seasonal anomalies in otherwise fairly predictable regional weather patterns. q: HOW COULD THESE fAILURES HAVE BEEN pREVENTED OR RECTIfIED? Angie: Communication is key. The client should be able to communicate with the designer and contractor as to what they want the roof to do for them, and in return the roof should remain an asset for the client. David: These and many other failures I have seen could have been averted with two items—better communication and alignment of expectations with potential outcomes, and a more thoroughly articulated and widely shared maintenance and operations plan developed during the design phase. Also better publicity and public education about what people could expect. q: WHAT ARE THE MOST COMMON TypES Of GREEN ROOf pERfORMANCE fAILURE? Angie: The projects I’ve evaluated are usually centered on plant failures which may be due to a lack of soil depth without proper irrigation shade levels or high heat stress. But some roofs have had soil erosion, especially at the edges. We have had a few roof leak calls, but the problem is typically traced back to the building structure rather than the green roof system itself. David: While there are isolated instances of catastrophic green roof failure, I believe the most common problems are in two areas: failure to achieve the potential that the green roof could provide if the roof were more integrated into building function; and failure for the vegetation that is planned to achieve and sustain proper establishment. These are cases where through poor design, construction, and/or maintenance, the vegetation does not become well established, is spotty, weedy, or otherwise not robust in parts or in total. Vanessa: Installers being pushed by owners and architects to install system and plant material too late or too early into the season in their respective climatic regions. Also, lack of species diversity in selecting and placement of plant material leaves very little resiliency should the selected specie(s) not thrive in that specific location, for one reason or another. Finally, lack of commitment on the owner’s end to monitor, establish and maintain the entire vegetative system. q: IN yOUR OpINION, WHAT ARE THE MOST COMMON CAUSES fOR GREEN ROOf pERfORMANCE fAILURE? Angie: I have seen a few failing roofs due to design—for example a module system that was dramatically cut to fit into a specific curved layout. A lack of “ownership” where the roofing responsibilities are awarded to many trades during construction is a common failure. Also, inexperienced designers or contractors responsible for the execution may also be at fault. Beyond installation and establishment, ongoing green roof maintenance is the most common cause. David: I believe the most common causes for failure fall into three categories: lack of adaptation of green roof technology to the actual conditions on a particular roof; failure to match expectations with potential outcomes; and/or failure to define, fund, and perform appropriate maintenance, especially during establishment, which can take LIVING ARCHITECTURE MONITOR / fALL 2012 / 6

Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Fall 2012

Green Roofs - Living Architecture Monitor - Fall 2012
Contents
From the Founder
Letter From the Editor
The World’s First Bio-Façade Ready to Grow
Save the Dates for the Greenroofs & Walls of the World™ Virtual Summit 2013
On the Roof With…
Policy and Standards
Current Research
Leadership
Product
Plant
Project
2012 Awards of Excellence
New Corporate Members
Professional Calendar
GRHC Buyer’s Guide
On Spec

Green Roofs - Living Architecture Monitor - Fall 2012