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20 Canadian Roofing Contractor & Design - APRIL / MAY 2007
the United Nations Commission on
the Environment and Development,
dates back to 1987. The UN Commission
defined “principles of environmental
sustainable development” as: Development
that meets the needs of the present
without compromising the ability of future
generations to meet their own needs.
The First International Conference
on Sustainable Construction was held
in Tampa, Fla., in 1994. Attendees defined
sustainable construction as: The
creation and maintenance of a health
built environment based on ecologically
sound principles and resource efficiencies.
The definition for sustainable roofing
most experts cite today is the one
used in the proceedings of the Sustainable
Low-Slope Roofing Workshop
held at the Oak Ridge National Laboratory
facility in Oak Ridge, Tenn., in
October 1996. At the workshop, a sustainable
roof was defined as A roof system
that is designed, constructed, maintained,
rehabilitated and demolished with
an emphasis throughout its life cycle on
using natural resources efficiently and
preserving the global environment.
Life Cycle Assessments (LCAs) are
science-based studies designed to measure
the environmental impact of a
product through its entire life cycle.
The objective of an LCA is to examine
and uncover all the important environmental
factors involved in the production,
use and disposal of a product – a
“cradle-to-grave” analysis that yields
what is called an ecoprofile. In the case
of roofing products, some of the important
criteria an LCA examines include:
• Material Extraction Costs: Environmental
impact of obtaining and
transporting raw materials.
• Manufacturing Waste: The
amount of wastewater and solid waste
generated during the manufacture of
the finished roofing product.
• Hazardous Waste: The amount
of toxic emissions resulting from the
extraction of raw materials, manufacture
and transport of the finished product
and installation of the roofing system.
• Embedded Energy: The amount
of energy required to extract, transport,
manufacture, deliver, install, maintain
and discard a roofing product during
its life cycle.
• Recycling and Re-use: The potential
for a used roofing product to be
recycled or re-used in another form.
LCAs are very complex and results
can vary depending on methodology,
underlying assumptions and, unfortunately,
the source of funding. LCAs are
used today primarily as guidelines for
establishing or defining standards, and
in the design phase of product development.
The U.S. Green Building
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Council has formed a task group to
study the feasibility of applying LCA
findings toward practical use in building
and construction. Various other
industry groups have already concluded
that, while LCAs are interesting and
useful as guidelines, they are not likely
to be adopted for practical purposes by
the building and construction industry.
In their Primer on Sustainable Building
Design, the Rocky Mountain Institute
maintains that sustainable roofing
can be accomplished in five different
ways:
• Recycled content in the roofing
product.
• The use of recycled materials,
such as thermoplastics or metal.
• Extended service life.
• More efficient use of energy and
other natural resources.
• The actual renewal of natural resources.
A more thorough, practical guide to
sustainable roofing – The Tenets of
Sustainability – was published by the
International Council for Research and
Innovation in Building Construction
(CIB) in 2000 after five years of com-