TechPractices are outstanding housing projects throughout the U.S. where innovative technologies are implemented. Builders and remodelers can use these examples as models for projects of their own.
| 21st Century Townhouses Snapshot |
| Location: |
Upper Marlboro, Maryland |
| Builder: |
NAHB Research Center |
| Project Scope: |
4 Townhomes |
| Price: |
$180,000+ |
| Financing: |
Market |
| Innovations: |
Energy Efficiency and Alternatives to Lumber |
Summary
In 1996 the NAHB Research Center, Inc. built four 21st Century
Townhouses to test, demonstrate, gain experience, and disseminate
information about innovative home building products, systems,
and technologies. The objectives of the project were to demonstrate
energy efficient construction using alternatives to lumber.
Through a competitive process, sponsors from the private sector
were selected to donate products and services to meet the project
goals. Many also contributed funds to help cover construction
costs. Other companies and public organizations donated products,
services, or funds to help build the 21st Century Townhouses.
Through research, demonstration, and evaluation, the NAHB Research
Center, Inc. is trying to help move promising new technologies
into mainstream construction, and to help home buyers get the
highest quality and greatest value available.
Details
Each of the four townhouses featured different foundation and
structural systems, energy-efficiency features, and lumber alternatives.
The systems and technologies incorporated into each of the homes
are summarized in the following table.
|
System |
House #1 |
House #2 |
House #3 |
House #4 |
|
Foundation |
Insulated concrete form basement with uninsulated slab floor |
Insulated concrete form basement with uninsulated slab floor |
Insulated concrete form basement with uninsulated slab floor |
Pre-cast concrete foundation |
|
Structural System |
Structural insulated panels (SIPs) containing 3.5 inch EPS (walls) and 7.5 inch EPS (roof) |
Insulated concrete form walls. Blown-in fiberglass roof insulation. |
Light gauge
steel framing with spray-in foam insulation. |
Lightweight
autoclaved aerated concrete block (R-10). Blown-in fiberglass
roof insulation. |
| Attic/Roof |
Structural insulated panels. Standing seam steel roof with high recycled
content. |
Raised-heel wood roof truss. Standing seam steel roof with high
recycled content. |
Steel-framed raised-heel roof truss. Standing seam steel roof
with high recycled content. |
Wood-framed, raised-heel truss. Standing seam steel roof with
high recycled content. Solar
electric roofing material covers part of roof.
|
|
Exterior Finish |
Exterior insulation and finish system (EIFS) |
Exterior insulation and finish system (EIFS) |
Exterior insulation and finish system (EIFS) |
Fiber-reinforced concrete stucco. |
|
HVAC |
Gas engine heat pump |
Gas furnace that also produces hot water. High efficiency air
conditioner. |
Ground source
heat pump for heating, cooling, and domestic hot water. |
Gas furnace that also produces hot water. High efficiency air
conditioner. |
|
Other |
Engineered wood I-beams, low-e glazed argon filled windows, insulated
steel door. |
Drainwater
heat recovery system. OSB sheathing, argon-filled low-e windows,
insulated steel door. |
OSB sheathing, foam-core steel door, argon-filled low-e windows,
insulated steel door |
Engineered
wood I-beams, insulated doors, low-e glazed argon filled
windows, insulated steel door. |
Installation/Construction
The evaluation of construction was not intended to be quantitative.
Qualitative information was gathered on "Buildability"
with respect to the large number of new and innovative materials
and systems incorporated into these homes. During construction,
materials and systems were evaluated on the basis of technical
performance, capability of the average contractor to install,
and infrastructure for the adoption of the technology such as
availability of technical information and code. A report detailing
the construction of the townhouses is available from the NAHB
Research Center, Inc.
Benefits/Costs
The construction of the 21st Century Townhouses provided a
lab for the evaluation and collection of valuable information
on many innovative products and systems. The project confirmed
that a large variety of innovative systems could be successfully
integrated to produce quality homes. Construction costs for this
demonstration project were not documented due to the large amount
of donated products and services.
Code/Regulatory
Compared to conventional construction, far less information
was available for the innovative structural systems used in the
townhouses. There were substantial delays in obtaining permits
for the homes due to the lack of supporting data on the many new
technologies used in the project. The lack of data was most pronounced
in the area of fire protection. Compliance documents were developed
by the NAHB Research Center, manufacturers and the local fire
department to satisfy the regulatory requirements. A major challenge
facing the manufacturers and suppliers of innovative materials
is the development of sufficient information and data to support
the widespread use of their products.
Feedback
Energy performance of each townhouse was modeled for and monitored
during the heating and cooling seasons. Simulated energy use for
each home exceeded Model Energy Code simulated energy use by between
22 and 58 percent. Actual energy use for the monitored year (homes
were unoccupied) closely matched simulated use. Focus groups were
conducted for the sponsors to provide a qualitative assessment
of the technologies. After the townhouses are open to the public
for a one- to two-year period, they will be placed on the market
and sold. The selling of the homes is the final, and perhaps the
most important test that innovative products face, that of consumer
acceptance.
Contact(s)
Do you have a specific question? Try the contacts listed below:
NAHB Research Center, EVHA Coordinator
400 Prince George's Boulevard
Upper Marlboro, MD 20774-8731
800-638-8556
www.nahbrc.com
American Iron and Steel Institute
1101 17th Street, NW, #1300
Washington, DC 20036
202-452-7100
www.steel.org
Armstrong World Industries
P.O. Box 3001
Lancaster, PA 17604
717-397-0611
www.armstrong.com
Benjamin Moore and Company
51 Chestnut Ridge Road
Montvale, NJ 07645-1862
201-573-6620
www.benjaminmoore.com
Hearth, Patio & Barbecue Association
North Kent Street, #1001
Arlington, VA 22209
703-522-0086
www.hpba.org
Icynene
5805 Whittle Rd, Suite 110
Mississauga, Ontario
Canada L4Z 2J1
905-890-7325
www.icynene.com
Maryland Energy Administration
45 Calvert Street
Annapolis, MD 21401
800-72-ENERGY
www.energy.state.md.us
Masonite
U.S Head Office
1 North Dale Mabry, Suite 950
Tampa, Florida 33609
800-895-2723
www.masonite.com
National Ready Mixed Concrete Association
900 Spring Street
Silver Spring, MD 20910
301-587-1400
www.nrcma.org
Portland Cement Association
5420 Old Orchard Road
Skokie, IL 60077
708-966-6200 x348
www.cement.org
Superior Walls
937 East Earl Rd.
New Holland PA 17557
800-452-9255
www.superiorwalls.com
Therma-Stor Products
1919 South Stoughton Road
P.O. Box 8050
Madison, WI 53708
800-533-7533
www.thermastor.com
iLevel by Weyerhaeuser (formerly TrusJoist)
33663 Weyerhaeuser Way South
Federal Way, WA 98003
888-iLevel8
ilevel.com
United States Gypsum Company
125 South Franklin Street
P.O. Box 806278
Chicago, IL 60606
312-606-5850
www.usg.com
U.S. Department of Energy
1000 Independence Ave. SW
Washington, DC 20585
202-586-5575
www.doe.gov
U.S. Environmental Protection Agency
Ariel Rios Building
1200 Pennsylvania Avenue, N.W.
Washington, DC 20460
202-272-0167
www.epa.gov
U.S. Department of Housing and Urban Development
415 7th Street SW
Washington, DC 20410
202-708-1112
www.hud.gov