Green Roofs - Living Architecture Monitor - Fall 2012 - (Page 18)

PROJECT PROFILE on the concePt oF FaiLure WHy GREEN ROOf AND WALL fAILURE CAN BE A GOOD THING By: pATRICK CAREy T here are many ways a green roof can fail. It can leak or fall down. The plants can die or never fully develop. These are the most commonly understood kinds of failure. There are other kinds of failure such as a failure to fit into the evolutionary direction of the surrounding ecology. There might even be failures that are unforeseen, like attracting a particular animal that is unwanted or producing an unacceptable runoff. The very idea of failure is hard to swallow. So, designers come up with pseudonyms like “lessons learned” or “unexpected development.” To mention a word like “failure” or “mistake” is not an acceptable business strategy for most designers, manufacturers or in- stallers. Businesses are nervous about competition. However, being able to risk failure, leads to breakthroughs and expanding knowledge. One reason why you see so many flat sedum green roofs whose only function is to retain stormwater is that the fear of trying other species or other slopes or other functions is a risk. I would call this a failure of design courage. When I first started designing and installing green roofs, there was no local market for them. So, we would put them anywhere that had a roof. Chicken coops, single car garages, storage sheds, anything that was low liability. This allowed us to fail in ways that allowed us to learn. So, we took on designing different growth media, selecting different kinds of plants, using different kinds of geotextiles and having projects in widely different regions. We had some leaks. We had some plants that would either die or not fully establish. We had runoff that stayed brown for a very long time. We had weeds. All of these things can be classified as failures. However, I have to say that, when compared to many companies that stuck with either the product they manufactured and sold, or designers who only mimicked successes of others, I concluded that we were on the right path. Designers rarely want to return to past projects. So, when the maintenance staff a few years later starts to redesign the plant list or amend the soil mix because the roof is not performing well, the designer is rarely concerned. I have seen this happen with a fairly large number of award winning green roofs and living walls. I always thought that design awards should be up for renewal every two or three years, just to keep the designers and installers honest. One example is a green roof near Seattle where the landscape architect specified potting soil instead of a proper growth medium. The perlite in the medium percolated to the surface and blew away. The result was a compromised aeration and hydrology in the growth medium that affected the soil biology and structure. Plants died and stopped holding down the medium. The medium started blowing away. LIVING ARCHITECTURE MONITOR / fALL 2012 / 18

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

Green Roofs - Living Architecture Monitor - Fall 2012
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
2012 Awards of Excellence
New Corporate Members
Professional Calendar
GRHC Buyer’s Guide
On Spec

Green Roofs - Living Architecture Monitor - Fall 2012