the following learning objectives to focus your study while reading
this month’s ARCHITECTURAL RECORD / AIA Continuing Education article.
reading this article, you will be able to:
Define the four-part life cycle of a building material.
List alternatives to high-VOC materials.
Explain how indoor air quality is improved by selecting sustainable
4. Explain how to get green
materials specified and into a building.
Understand what questions to ask in order to evaluate the sustainability
of a material.
About five years ago, Marsha Maytum, aia, began a search for
sustainable materials to use for the renovation of the Thoreau
Center for Sustainability. Located in the National Historic Landmark
District of the Presidio in San Francisco, the office space for
the Thoreau Center was to become a model of sustainable design
for the National Park Service. Maytum's firm, Tanner Leddy Maytum
Stacy Architects, was interested in incorporating ecological design
and materials in their projects. "All of the partners were trained
in the 1970s," Maytum says. "Here was a chance to use that knowledge
and ideology to create something we really believed in."
The Thoreau Center was to set the standards for the rest of the
development at the Presidio, a former U.S. Army base with about
500 buildings to be redeveloped. Because the project fell under
the scrutiny of the National Park Service and because the historic
nature of the building required that the architects meet the secretary
of the interior's Standards for Rehabilitation of Historic Structures,
getting the right materials for the project was essential.
But sustainable, or "green," materials (the terms are used interchangeably)
are not so easy to identify. Maytum discovered what environmentally
conscious architects are realizing everywhere: Understanding a
material's degree of sustainability is an elusive task. It's not
simple and straightforward like comparing calories or grams of
fat. While there are many books, magazines, Web sites, trade organizations,
and journals that address the subject, sifting through all this
information takes a tremendous amount of time.
Maytum ultimately hired an environmental consultant to help set
up a process for selecting the materials for the center. The renovation,
completed in 1998, meets the goals set for the space by the park
service. The fully leased office spaces are, for the most part,
naturally ventilated with operable windows. Recycled and environmentally
sensitive products are used throughout, and 73 percent of the
materials removed during the renovation were recycled.
Maytum says her firm's practices have changed as a result of
the project. They found that designing a green building mandates
a different approach than standard design work. "You don't do
everything the same and then slip in green materials here and
there," she says. "It's a holistic process."
Maytum's firm also has a better understanding of the cost implications
of green building. "We've been able to incorporate the products
used in the Thoreau Center in our other projects. In looking at
the construction costs, we know that the choice of sustainable
materials adds less than 1 percent to the overall hard costs of
a building. That is a small slice of the pie that is easily compensated
for in the quality of the space."
Shades of green
A sustainable building starts with the quality of its components,
as measured by their environmental impact. There are many variables
to take into account while evaluating the components, including
the way they will be used, the amount that is specified, and aesthetics.
In designing the World Resources Institute's new offices in Washington,
D.C., for example, Sandy Mendler, aia, of Hellmuth, Obata and
Kassabaum, used wheat-straw MDF extensively for the casework and
the doors. "With standard doors, the core typically contains formaldehyde
and the surface may be wood from a nonsustainable source," she
says. Mendler designed doors using straw particleboard as the
surface over a hollow core made of recycled paperboard. While
the exposed-straw look used there and in the casework might not
look right in other buildings, it works here.
The language of sustainability is also imprecise: What do terms
like embodied energy and high recycled content mean? To add to
the confusion, many of the companies making green materials are
young and unstable. They go in and out of business, merge, and
change the names of their products. Many are regional and hard
to find. Green washing, or issuing false claims about sustainability,
is another problem. Dru Meadows, aia, who consults on environmental
issues and specifications, keeps a file of advertisements and
brochures from companies guilty of green washing. "There's an
ad for a $179 Teddy bear that is marketed as green because it's
made of recycled mink," she says.
The first thing architects must understand is that there are
shades of green; "this is not a yes-or-no question," Meadows says.
"The ideal sustainable material would have no adverse impact and
might even play a restorative role in the planetary ecosystem.
But this material does not exist, not on any sizeable scale anyway."
Instead, a material must be evaluated according to its life cycle.
This consists of four general stages: Raw material, manufacture
and transportation, tenure in the building, and disposal or reuse.
Understanding how each of these phases affects the environment
is the key to understanding sustainability.
In the beginning
At the raw-material stage, concerns revolve around the impact
of mining, harvesting, or extraction practices. These concerns
evoke vivid images of destruction, such as the enormous tailings
piles generated by large mining operations and the widespread
clearcuts of industrial forestry. Using materials with recycled
content proportionately reduces the amount of raw material taken
from the land and, at the other end of the scale, the amount of
waste that reaches landfills. While many materials have some recycled
content, the type and amount varies. Industrial waste, such as
the flyash from coal-burning power plants used in some cement
mixes, differs from postconsumer recyclables, such as milk jugs
and newspapers. Recycled content is high if it makes up 50 percent
or more of a product. Plastic lumber contains more than 90 percent
recycled content; cellulose insulation consists of about 80 percent
At the Thoreau Center, special efforts were taken to ensure
that the new window frames contained 80 percent recycled aluminum.
"The aluminum supplier was worried that the client wouldn't accept
the imperfections from the recycled content. We had to convince
him that this client wouldn't mind," Maytum recalls. Other materials
with high recycled content used at the center included ceiling
tiles, carpet, cotton insulation, and particleboard used for the
Still, recycling isn't always a clear winner environmentally.
It may take more energy to collect and process waste materials
than it does to put them in a landfill. For example, data suggests
that more energy is embodied in cellulose insulation than in fiberglass
because of the cost of recycling the newspapers. Embodied or embedded
energy is the energy used to create a product. There are publications
that provide this information, but it is often overemphasized
at the expense of other, less quantifiable factors, such as habitat
disruption or the amount of chemicals leaching from a tailings
Forestry operations can be better or worse environmentally,
and sustainability certifications are myriad and inconsistent.
An architect in California, for example, thought he had selected
a certified wood for a major public project, but had to change
his specifications when an environmental group discovered that
the wood was not sustainably harvested, despite the certification.
The problem is that most certification programs are not overseen
by environmental organizations. This is particularly true of governmental
certifications of tropical wood .
A worldwide standards-setting initiative by the Forest Stewardship
Council (FSC), based in Oaxaca, Mexico, has emerged as the program
most acceptable to environmentalists. Its American counterpart,
the Certified Forest Products Council in Beaverton, Ore., is a
network of wood suppliers and distributors whose products are
certified by FSC. The logo is stamped on the wood or printed on
the product label.
A product that doesn't harm the environment in its raw-material
phase may cause ecological destruction during the manufacturing
process. Petrochemicals used to make plastics, adhesives, and
coatings are often toxic at various stages during their manufacture.
The formaldehyde-free isocyanate binder used in wheat-straw particleboard,
for example, while stable and safe once it is cured, is highly
reactive and hazardous to workers at the factory. Nearly all petrochemical-based
paints, adhesives, and resins used in construction materials are
made from chemical building blocks, such as styrene and benzene,
which are highly toxic and carcinogenic during manufacture.
Plastics are believed to be inert once installed, though heat
breaks them down and releases petrochemicals. PVC, for example,
present in furnishings, plumbing, and other products, releases
hydrochloric acid when it is heated, says Kirsten Childs of Croxton
Collaborative Architects. For that reason, she avoids specifying
products that contain it.
Metal, glass, and cement are energy intensive to manufacture,
resulting in significant emissions from the fuels used to generate
that energy. In the case of cement, carbon dioxide (CO2) is released
not only from the fuels but also from the limestone as it undergoes
chemical transformations in the cement kiln. Industrial by-products,
such as ground blast-furnace slag from steel mills, can replace
much of the cement in concrete, reducing CO2 emissions.
Transportation is a factor to consider with any material. Selecting
local materials reduces the amount of fuel used in transport,
keeps money within the community, and contributes to an awareness
of the products, materials, and climate-specific construction
features that make each region unique-an important component of
ecological awareness. For example, Payette Associates used locally
grown certified wood and slate taken from a nearby quarry when
designing the 190,000-square-foot Bicentennial Hall, a laboratory
and classroom building for the sciences at Middlebury College
in Middlebury, Vt.
The Athena Institute, a Canadian organization that researches
the environmental impacts of building materials, estimates that
between 10 and 30 percent of the energy associated with the manufacture
of wood, concrete, and steel in Canada is related to transportation
of the raw and finished materials. Further studies show that trains
are eight times more efficient than trucks for moving materials,
and ships are twice as efficient as trains.
The great indoors
Green materials contribute to the quality of the indoor environment,
as affected by air, lighting, water consumption, durability of
the building, and overall comfort, factors that are not as easily
quantified as savings on utility bills, but that have a positive
impact on the building and its occupants. Studies by the Rocky
Mountain Institute and the U.S. Department of Energy have documented
increases in occupant productivity in some buildings that dwarf
the dollar value of the energy savings.
This was true at VeriFone, Inc., a 76,000-square-foot manufacturing
and warehousing facility in Costa Mesa, Calif. The manufacturers
of electronic equipment have documented significant improvements
in productivity, fewer errors, and less absenteeism. Designed
by Croxton Collaborative Architects and completed in 1993, the
building has been studied over the past few years to evaluate
the effects of including green materials, such as solution-dyed
carpeting, which features dye that is integral to the fibers-an
efficient way of applying dye that introduces few chemicals to
"A manufacturing facility was not considered the ideal setting
for green design," says Randolph Croxton, faia. It was normally
reserved for showcase buildings that proved something about the
ideology of the company. "The owners wanted a project that would
change the culture of the company and inform subsequent buildings.
I was convinced that a drastic improvement in productivity would
result and lead to financial benefits." Research has borne this
sustainable is it?
Will the material minimize energy use?
Will the material adversely affect the health of building
Is the material likely to need frequent replacement, special
treatments, or repairs?
Are there significant impacts from the process of mining
or harvesting the raw materials?
Are significant toxic or hazardous by-products created
during the manufacture of the materials, and do these
by-products pose a risk of exposure to workers or the
How much nonrenewable energy is consumed in the manufacturing
How much solid waste is generated during the manufacturing
Are any of the raw materials from rare or endangered resources?
Are the raw materials and/or manufacturing locations far
from the building site?
Can the material be reused or recycled?
Indoor air quality (IAQ) directly relates to the construction
materials and furnishings used. Choosing the greenest materials
is one way to address the problem. Any finish products that are
applied in wet form, such as paints or adhesives, usually contain
volatile organic compounds (VOCs). But there are versions of most
of these that have no VOCs. This is especially important if a
coating needs to be reapplied when the building is occupied, Childs
says. "These VOC-free paints and adhesives are hard to find. They
are often manufactured regionally and have a shorter shelf life
than those that are loaded with chemicals," she says. "But they
are worth the search."
Carpets have also been associated with IAQ problems, primarily
from the sytrene butadiene (SB) latex backing. The Carpet and
Rug Institute has created a monitoring system, and the amount
of off-gassing has been greatly reduced as a result. In spite
of these improvements, some architects still strive to minimize
their clients' exposure to SB latex.
Whether it's an individual product or a whole building, if it
lasts longer, its environmental impact is amortized over a longer
period of time. All other things being equal, a more durable material
is a better environmental choice. Smart design is important here,
too, however. If a durable material is intricately bound up in
an assembly with short-lived products, it may be replaced before
its time. Also, some interior finishes are replaced frequently
owing to the demands of fashion, so they may not be the appropriate
place to invest in durability.
To the landfill
How a material is handled once it is removed from the building
should be determined when it is specified, Meadows says. Materials
that are easily recycled, minimally processed, or biodegradable
are best. Making it easy for materials to be isolated for reprocessing
will improve the odds of future recycling. Wood treated with preservatives,
such as chromated copper arsenate, works well during its life
in the building but poses problems in the waste stream. It is
almost impossible to recycle and is not safe to incinerate or
deposit in landfills. A better choice would be to use recycled
Specifying green materials accounts for just one step in the
environmental design process. And even if a product is listed
in the specs, it won't necessarily end up in the building. Environmental
criteria must appear prominently in the specs, especially if substitutions
will be allowed. Meadows recommends adding an "environmental requirements"
article to each technical section in which green products are
specified. Otherwise, these requirements might not be noticed.
She also suggests listing contact names for any nonstandard products.
The architect might even call the manufacturers and alert them
to the fact that a project is going out to bid with their products
Architects who use unconventional materials must be prepared
to document their performance. At the World Resources Institute,
"absolutely everything was challenged by the contractor and subcontractors,"
Mendler says. Having other members of the team involved from the
onset of the project helps. "This is all so much simpler as long
as everyone starts out making the environment a priority," she
adds. "Incorporating sustainable materials is, more than anything,
a matter of habit. When you're used to a material, it is hard
to change to something new. But when everyone is working together,
that effort is minimized. And it becomes worthwhile."
Environmental Building News Product Catalog, organized by
CSI number, includes a green-products directory, descriptions
of more than 1,300 green products, and a binder of product
Building News also publishes a monthly newsletter with reviews
of green-building products and analyses of design strategies.
REDI Guide is a free, online database of green-building
products searchable by product name or CSI number. www.oikos.com
AIA's Environmental Resource Guide consists of material
reports with detailed life-cycle analyses of most major
building materials. Reports compare the environmental profile
of various materials for a particular assembly or function.
Case studies are also included. Available as a three-ring
binder or CD-ROM. John Wiley & Sons. 800/225-5945.
West Coast Architectural Resource Guide and Database by
the Northern California chapter of Architects/Designers/Planners
for Social Responsibility (ADPSR) is a comprehensive listing
of green products for the region. It's available either
in paperback or on CD-ROM. 510/841-1039.
Guide to Resource Efficient Building Elements is an annotated
paperback directory of materials for residential and small
commercial construction from the Center for Resourceful
Building Technology. 406/549-7678.
Harris Directory is a reference for recycled-content building
materials. Online subscription available. www.harrisdirectory.com