Green Roofs - Living Architecture Monitor - Summer 2016 - 20

STANDARDS OVERVIEW: THE NEW ASTM GUIDANCE FOR GREEN ROOFS WRITTEN BY BRUCE DVORAK In June, 2014, the American Society for Testing and Materials (ASTM) published E2777 - 14, Standard Guide for Vegetated (Green) Roof Systems. It was written by a sub-committee of some of the top green roof experts in North America. This marks the first comprehensive North American guideline for green roofs from a major guidelines publisher. G uidelines are particularly important where the articulation of green roof properties and performance measures are required for nonproprietary competitive bidding. This article reviews one of the major advances of the new guideline for the North American green roof industry: the articulation of green roofs at the system level. Understanding green roofs as systems developed out of Europe, the first and most commonly cited and used guidelines for green roofs worldwide are the Guidelines for the Planning, Construction and Maintenance of Green Roofing, commonly referred to as the German FLL Guidelines for green roofs. Prior to the publication of ASTM E2777 - 14, the one existing guideline and four standards published from ASTM covered individual aspects of green roofs such as guidance for selecting vegetation, a standard practice for structural weight calculations, and standard tests for inspecting growth and drainage media porosity and weight. These methods are critical for those involved with design, policy, permitting, construction and performance evaluation, but in isolation they don't provide comprehensive support because the healthy functioning of a green roof is much more than the performance of an individual component, it is the long-term systematic interdependence of its parts. There are more than a few examples of green roofs that have had complete or partial collapse of plant communities because system components were not well integrated. Substrates held too much moisture, were not stable and slumped over time, drainage layers were insufficient for the selected vegetation, and substrate depths were not adequate to support the root systems of the selected forms of vegetation. The new ASTM guideline addresses many of these issues. Although much guidance is provided, it is not a cookbook approach to the design of a green roof. It functions as a set of common factors from which to understand and specify as needed. The scope of ASTM E2777 - 14 is to define terminology, principles and fundamental concepts including goals for sustainability, construction and the integration of materials. There are over 38 terms defined with discussion and references to more than 30 other standards and guideline documents. Its fourteen pages address technical aspects regarding vegetation, growing media, wind scour resistance, soil reinforcement, separation or filter layers, drain layers, water retention layers, protection layers, and root penetration barriers. The guideline makes great progress to integrate the knowledge and recommendations of the existing ASTM green roof guidelines and standards by addressing the layers of green roofs, construction methods, critical issues, Northeast Green Roof Experts GREEN ROOFS, LLC 9 Olive Square Somerville, MA 02143 office: 617.764.1310 fax: 617.207.4341 info@recovergreenroofs.com www.recovergreenroofs.com Private Residence Winchester, MA Extensive Green Roof Call us today 1,300 sq. ft for a free consultation LIVING ARCHITECTURE MONITOR / SUMMER 2016 / 20 450 Artisan Way Assembly Row Somerville, MA Mixed-Use Roof Terrace Fenway Farms Boston, MA Rooftop Farm Harvard Business School Class of 1959 Chapel Boston, MA Extensive Green Roof 6,100 sq. ft. 7,000 sq. ft THIS ISSUE ONLINE AT LIVINGARCHITECTUREMONITOR.COM 1,000 sq. ft READ http://www.recovergreenroofs.com

Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Summer 2016