Durability
Buildings Home >
Sustainable Design > Durability
Huff and Puff: You Can’t Blow These
Green Homes Down
by Ryan Puckett
While disasters and the devastating impacts grab headlines, durability
is becoming a top of mind issue in the sustainable housing movement.
After much initial focus on energy efficiency, the green building
industry is now beginning to consider durability right alongside
it.
According to a recent survey of homeowners by the Portland Cement
Association (PCA), the top two characteristics of most importance
are durability followed by energy efficiency. “Economically,
we can’t continue to build the same way,” says Lionel
Lemay, vice president of technical resources for the National Ready-Mixed
Concrete Association. Lemay refers to the destroyed homes from recent
flooding, tornadoes, hurricanes, and wildfires.
Rebuilding the same structures that failed in the first place seems
wasteful to Lemay.“But building smarter can’t be mandated,”
explains Lemay.“We need to provide incentives.” And
the incentives need to extend to homeowners, builders, and developers.
 |
| This “Fortified...For Safer Living”
home in Bolingbrook, Ill., is expected to earn an ENERGY STAR
rating. Photo courtesy of Dukane Precast, Inc. |
One such initiative is “Fortified… for Safer Living,”
a new-home construction designation program of the Institute for
Business & Home Safety (IBHS). The Florida-based “Fortified”
program specifies construction, design and landscaping guidelines
to increase a new home’s resistance to natural disaster from
the ground up.
To date, there are approximately 2,500 “Fortified” homes
completed, under construction or planned in 10 states throughout
the U.S. Of that number, 1,500 feature a concrete wall system of
one form or another.
In the Chicago suburb of Bolingbrook, Ill., where tornadoes frequently
threaten homes, an entire subdivision is being constructed with
precast concrete walls. A 2,800-square-foot home was the first "Fortified"
home in Illinois.
“This home utilizes a systems approach with our ‘double-wall’
precast concrete product to build the safest, healthiest, most durable
and energy-efficient structure possible,” said Brian Bock
of Dukane Precast, Inc.
Tests conducted at Texas Tech University showed that concrete wall
systems suffered no structural damage when impacted by debris carried
by hurricane and tornado-force winds; a testament to concrete’s
durability.
The walls have foam insulation in the middle, encapsulating it in
concrete. Inside the precast floors, radiant heat provides a cost
effective method of heating. Even the garages employ this energy-efficient
technique.
According to Bock, while radiant heating can be applied to a number
of construction applications, the thermal mass of concrete offers
the most energy efficiency.
Building Programs
 |
This zero-energy home incorporates renewable
energy production via rooftop solar
panels and stores excess solar energy in its plaster walls,
concrete floors and interior masonry.
Photo: AndersonSargent Custom Builder LP of Waxahachie, Texas. |
Companies like Dukane Precast are also partners with the U.S. Department
of Energy’s Building America program, a private/public partnership
conducting research to find energy-efficient solutions for new and
existing housing that can be implemented on a production basis. Homes
in the Building America program strive to be up to 70 percent more
energy efficient than their conventional counterparts.
Programs like Building America are critical for the increased interest
from homebuilders trying to build more energy efficient homes. The
program’s research will help lead to “zero-energy”
homes, reduced construction time and waste, improved builder productivity,
and implementation of innovative energy- and material-saving technologies.
Award-Winning Construction
At the 2006 International Builders’ Show, Building America
delivered the Energy Value Housing Awards (EVHA). The awards honor
builders who voluntarily incorporate energy efficiency into all
aspects of new home construction. Among the top-level “gold”
winners was a Dallas home featuring Durisol Wall Form System insulating
concrete forms (ICFs), and built by AndersonSargent Custom Builder,
LP. The judges were impressed with the home’s outstanding
energy performance and exemplary use of systems engineering including
the ICF envelope.
Studies have demonstrated that ICF exterior walls alone can help
a home require 44 percent less energy to heat and 32 percent less
energy to cool than a comparable frame home.
Tierra Concrete Homes, Inc., earned a “silver” EVHA
thanks in part to its insulated tilt-up concrete wall system for
their Pueblo, Colo., home. The judges noted the entry features “an
excellent product combining passive solar features with new technology.”
The precast walls are integral to the passive solar design.
Jim Niehoff, residential promotion manager for the Portland Cement
Association, notes that concrete homes are becoming more prevalent
in the marketplace, thanks to their energy efficiency, durability
and disaster resistance, quiet interior, and indoor air quality.
“The homebuilding industry is definitely taking notice,”
says Niehoff. In addition to the attention from “Fortified…for
Safer Living” program and promotion of wind-resistant construction
by groups such as the American Red Cross, Niehoff points to The
New American Home (TNAH) as evidence of concrete’s increasing
acceptance for single-family homes.
TNAH, the feature show home for the International Builders’
Show, has featured a concrete wall system each year since 2004.
The 2004 Las Vegas home featured ICFs supplied by Arxx Building
Products for the home’s envelope and an abundance of decorative
concrete throughout. Concrete masonry has been used for the last
two versions of TNAH in Orlando, and in 2007, Niehoff says the home
will be built with an insulated precast system.
A Quick Primer To The Various Concrete Homebuilding
Systems
INSULATING CONCRETE FORMS (ICFs) One of the fastest
growing methods of home construction in the U.S. involves the use
of ICFs, which represented 4.7 percent of the single-family market
for new construction in 2004. “Basically, ICFs are a foam
and concrete sandwich,” explains Jim Niehoff, PCA residential
promotion manager. The most prevalent system uses hollow, polystyrene
blocks that stack and interlock. Concrete is pumped into the cavity
to create a solid structure wall with insulation on both sides.
ICFs are increasingly popular for light commercial buildings and
multi-family housing.
PRECAST CONCRETE FORMS With precast technology,
large sections (or panels) of concrete walls are poured horizontally
in a carefully controlled factory environment, ensuring a very high
level of quality.The sections typically arrive by truck, are lifted
into place and fastened together. A layer of foam insulation is
incorporated within the wall at the factory, greatly enhancing energy
efficiency.“It can take literally four hours to erect the
walls for an entire home,” says Niehoff.
CONCRETE MASONRY This time-proven technique continues
to produce durable and increasingly sustainable structures, especially
when integrating a layer of insulation. For construction, masons
lay a series of courses (or rows) of concrete block bound with mortar.
The block walls are often reinforced with concrete pumped into the
block cavity.
REMOVABLE CONCRETE FORMS The granddaddy of concrete
forming has moved up from the basement foundation and into the market
for above-grade walls. With this system, a crew erects forms that
make a mold in the shape of the desired walls. Once steel rebar
is placed within, the concrete is poured into the cavity. Crews
then strip the forms to leave a concrete wall. In some cases, companies
design form liners so the home already has a decorative finish,
thereby saving time and eliminating the waste generated by cladding
the home. Again, a layer of foam insulation is the secret to maximizing
concrete’s thermal mass properties.
Ryan M. Puckett is a freelance writer, media liaison and copywriter.
|  |
|