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Orit of Orit Yanai Inc. demonstrates blending two
colors of earth plaster during application.
Photo courtesy of Orit Yanai Inc. and Anita Bowen
by Loretta Hall
Everyone agrees that “green” means
environmentally friendly. But
when it comes to deciding which
plasters can be considered green, it
depends on whom you ask.
Green means diff erent things
to diff erent people. Manufacturers
of all types of plasters can point out
characteristics that make their version
environmentally sound. Th e diffi culty
comes in comparing degrees of
“greenness” and in deciding whether
being green means sacrifi cing quality.
Indoor air quality
It is generally accepted that a
material’s off -gassing of volatile organic
compounds (VOCs) plays a critical
role in the defi nition of “green.” Some
people insist on zero-VOC content,
while others are satisfi ed with “low-
VOC” products, which have VOC
concentrations of 25 grams per liter or
less. “It’s important that the binders in
the plaster are not high-VOC content,”
18 ◆ www.Hawk-n-Trowel.com ◆ Spring 2008
Seeking
plasters
says Rye Hudak of Stonelace Designs
in Berkeley, Calif. “For example, it’s
not uncommon for Venetian plasters to
contain a high acrylic content. In that
arena, we would use a plaster that does
not rely on an acrylic binder and is more
traditional in composition.”
Despite general agreement that
lower VOC content corresponds to
greater greenness, there is room for
disagreement about the way standards
are written by organizations such as
Green Seal. “I think Green Seal should
rewrite the GS-11 certifi cation standards
in terms of grams per room, as opposed
to grams per liter,” says Doyle Self of the
School of Italian Plasters, which holds
classes in Dallas, San Diego and Verona,
Italy. He points out that one liter of his
company’s acrylic resin and mineralbased
Stucco Veneziano will cover 200
square feet. On the other hand, several
other Venetian plaster manufacturers
list coverage rates of 40 square feet to
80 square feet per liter. “When you look
greener
at how thick you have to put the other
stuff on, ours has actually less VOC per
room,” Self says. He also notes some
of his competitors’ VOC-free products
have to be waxed. “So you’re introducing
something that generally has high
VOCs on top.”
Another factor that aff ects indoor
air quality is mold prevention. Some
plaster manufacturers add chemical
biocides to their products, while others
use basic ingredients that naturally resist
the growth of fungi and prevent the
accumulation of moisture in walls. “Th e
reason why (synthetic paints and plasters)
were developed in the last hundred years
is because the general thought in the
United States was that buildings must be
waterproofed very thoroughly,” says Orit
Yanai of Orit Yanai Inc. in San Francisco.
“If you don’t allow breathability in your
walls, then eventually moisture will
gather up on the inside of your walls
and create dry rot and mold issues. Most
synthetic materials do not allow the