This article originally appeared
in the September 2006 issue of Architectural West magazine.
In the way that so many
great visions are first borne, architect Tom Ward’s initial ideas for improving the rammed earth building process were
sketched on the back of a cocktail napkin. Ward, a partner with Ward + Blake Architects of Jackson, Wyoming, was watching
a televised newscast of the aftermath of a Turkish earthquake and noticed that some of the region’s earthen structures
sustained less damage than the more modern buildings. As he considered the great challenge of building relief housing, Ward
saw a vast, untapped resource in the surrounding rubble. He knew, however, that traditional rammed earth buildings can have
structural weaknesses and wondered if there might be a way to stabilize the indigenous materials even further.
Ward’s cogitations eventually resulted in an idea to stabilize rammed earth walls with reinforced
steel rods in a “post tensioning system.” Teaming up with Joe Grill
of Nelson Engineering in Jackson, Wyoming, Ward says, “We did some mathematical calculations based on the reinforcing
idea, the thickness of the wall and its relative strength. The numbers led us to theorize that we could make a rammed earth
wall as a strong as a conventional eight-inch thick concrete block wall.”
Ward received a grant from
the Newton Foundation to construct four wall prototypes—built by Ward’s rammed earth construction mentor Jug Branjord
of Casper, Wyoming—and test those walls at the University of Wyoming Department of Civil and Architectural Engineering.
Loading the walls horizontally, the team carefully documented the strain gauges relative to the loads superimposed on them.
“When we tested the walls to failure, three out of four matched our theoretical strength calculations perfectly,”
Ward says. “After making some minor adjustments, the results were consistently repeatable.”
Earlier this year, Ward
was awarded a U.S.
intellectual property patent for his low-tech, high-functioning process for stabilizing rammed earth walls with reinforced
steel rods. “We didn’t invent the componentry; we simply put it together in a way that hadn’t been tried
before,” Ward says. “Fifty percent of the world’s population lives in earthen houses, many of them in seismically
active parts of the world. This strong, low-tech method could allow for the rebuilding of structures in areas ravaged by earthquakes—or
even for replacing existing structures to prevent future damage—without resorting to expensive, culturally foreign building
systems.”
In addition to the new
technique’s seismically resistant qualities, rammed earth structures are environmentally friendly – efficient
to heat and cool, and built with indigenous materials that blend into natural surroundings. Ward is finding out about these
properties first-hand, having just completed the world’s first “earthquake resistant” rammed earth residence—his
own 3,000-square-foot home. Perched on a hillside overlooking the Snake
River, the home blends easily into its surroundings, incorporating materials mined
from the site along with gravel pit by-products.
“I decided to try
the technique on my own home, because above and beyond all the rational test data, it met my criteria as an architect,”
Ward says. “I appreciated the sense of terroir, the coloration of the walls and the way they pick up the composition
of the surrounding rock structure.”
“This was also a
litmus test of sorts; prior to building our house we had submitted all testing data to local code officials. Obviously the
technique had never done before, but based on the quality of the test data and documentation by the University
of Wyoming, the Teton County Building Department accepted not only the technique
but the data and structural analysis as well.”
The building site, at an
elevation of 6250 feet, posed its own set of challenges. “It was a very steep, difficult, cramped site,” Ward
says, “but the views were spectacular. I designed a very simple form for a two-story house with a singular roof and
the main walls slightly angled and splayed to certain view corridors on the property; the cliffs behind our house were a special
focus. The ‘inverted V’ roof opens the house and liberates the views at the walls. The roof is fitted with interior
roof drains piped out on the site, so I can control where the runoff goes and by routing the water off the site we don’t
ever have an icicle or drip problem.”
“The 18-inch thick
earthen walls have a low R-value, but their high thermal mass naturally keeps the home warm in the winter and cool in the
summer. During the hottest days of summer, we button the house up and the walls have cooled sufficiently at night that they
don’t warm up very fast; the interior temperature of the house remains
constant. Then we open up the house at night and cool the interior of the house.”
In the winter, the home
is heated with a conventional oil-fired boiler and radiant slab floor heating. Concrete floors throughout the home keep it
clean and mold-free. “The heavy masonry construction has nice acoustic properties, too,” Ward says. “The
house is very quiet despite the large expanses of glass.”
Seven years have passed
since Ward first scribbled his ideas on a cocktail napkin, and he and his family
continue to marvel at the experience of living in the first home built from the now-patented process. “This house always
has an organic, ‘breathing’ feel to it,” Ward says. “In the evening, the breezes blow parallel to
the mountains and when you open the doors you can immediately feel the air migrating from one end to the other; you should
feel it after a rainstorm when the air is ionized.”
“We
really feel healthier in this house,” he adds. “It’s a very nice environment to live in.”
For more information, contact:
Tom Ward
Ward + Blake Architects
P.O. Box 10399
Jackson, WY 83002
(307) 733-6867
www.wardblake.com
tomward@wardblake.com
