Green Builder News - August 96


Green Builder News

A program of the City of Austin

August 1996



The Newsletter of the City of Austin's Green Builder Program

IN THIS ISSUE


Greening the Bottom Line

5th Annual Green Building Conference to attract participants from five-state area and Mexico

November 7-10, 1996
Austin Convention Center

Mark your calendars now for the 5th Annual Green Building Conference. Some of the nation's best and brightest experts on green building and sustainability will be here to inform, update, and energize you on how to make green building work for you or your business. Steve Loken with the Center for Resourceful Building Technology in Missoula, Montana; Barbara Harwood, Enviro Custom Homes, Dallas, Texas; and Peter Yost, National Association of Home Builders Research Center, Washington, D.C. are just a few of the nationally-known experts scheduled to speak. Thursday night's informal roundtable discussion with a panel of speakers will provide an eye-to-eye question-and-answer session with conference participants. The Friday and Saturday working session and trade show will be followed on Sunday by a tour of residential and commercial green buildings in Austin and the surrounding area. The conference is sponsored by the Austin Chapter of the American Institute of Architects, the National Association of Home Builders Research Center, the Lower Colorado River Authority, the Rocky Mountain Institute, and the City of Austin's Green Builder Program, as well as 14 other industry entities. For conference registration or trade show information: contact Nick Denner at (512) 264-0004 (nick_denner@greenbuilder.com).

For More info, visit the website at http://www.greenbuilder.com/conference/


Parade of Homes Goes Green

Between June 23 and July 13, over 25,000 people toured the 1996 Parade of Homes where eight of Austin's most prestigious custom builders made a conscious choice to build homes more environmentally-friendly than the typical home in Austin. These builders joined the City of Austin's Green Builder Program and made many green improvements in their homes.

The 1996 Parade of Homes builders were Tommy Livingston Construction, Tom Hobbs Company, Lloyd Homes, Inc., Wilde Custom Homes, Jauregui Architect-Builder, Scott Bryant Homes, Travis Homes, and Gregory Sells Builder.

Some of the green features included water-conserving turf grasses, plants and shrubs; attics made cooler with radiant barriers and continuous venting under the eaves and at the roof ridge; glues and paints with reduced levels of toxic fumes; construction using many recycled-content materials; high-efficiency cooling systems with all duct work sealed with latex mastic (not duct tape!) to reduce loss of conditioned air; backyard composting and space in a handy inside location for recycling bins. One home even displayed a photovoltaic system that converts sunlight directly into electricity for the home.

The 1996 Parade of Homes was presented by the Texas Capital Area Builders Association, hosted by developer Dwyer/Murphy Companies, and sponsored by the Austin American-Statesman. The homes are in the Parkstone at the Wilderness subdivision off Capital of Texas Highway.


Fly Ash and Stained Concrete Floors: Compatible or Not?

Stained concrete as the finished floor is showing up in homes and businesses around Austin. The Green Builder Program encourages this technique because it uses resources efficiently. We also promote using fly ash in concrete as a partial substitute for portland cement because it's an excellent use of a waste product and makes concrete stronger. However, some concrete stain manufacturers say that stains should not be used with concrete containing fly ash.

Calls by the Green Builder Program staff to Chem Systems, Inc., in Houston, TX (manufacturer of concrete stains) shed some light on this matter. According to owner Bruce Meikle, they did not recommend using their stains with fly ash concrete only because of concerns that fly ash might alter the color of the stain from their color card. Builders who use concrete stains with traditional concrete report that stains sometimes turn out different from the color card anyway. These variations can be attributed to differences in the concrete components and their origin.

Meikle informed the Green Builder Program that the company was in the process of updating its data sheets to indicate that colors could vary from the card for many reasons. Meikle is a strong proponent of using fly ash in concrete.

Concrete contractors could solve color questions by mixing a small batch before starting the job.

For more information, contact Bruce Meikle of Chem Systems, Inc., 1-800-545-9827.


Green Builder Wins Governor's Award

In April, members of the Green Builder Program accepted the Governor's Award for Environmental Excellence at a ceremony held in Austin. The award is given annually by the Clean Texas 2000 Program of the Texas Natural Resources Conservation Commission for the state's outstanding waste reduction and pollution prevention projects. The Green Builder Program won in the government category.

Laurence Doxsey, Jill Mayfield, and Mary McLeod
accept the state's Environmental Excellence Award
from Governor George W. Bush.


Product and Material News

Ener-Grid is a building wall system made of recycled, expanded polystyrene foam ground into small beads and mixed with portland cement. It is formed into 10 ft. long building units with horizontal and vertical cavities where reinforcing bars and concrete are placed. Foam-form wall systems are typically very energy-efficient, and because the polystyrene is mixed with cement, it is not subject to insect infestation. Although bugs don't eat polystyrene, they often nest in it and can be hard to remove. Ener-Grid is available through 3E Industries in Austin, (512)264-3462.

CDC Carpets and Interiors in Austin carries an extensive line of natural flooring products. Floor coverings made from wool, Texas mohair, cork, sisal, coir, linoleum, and jute are available. CDC Carpets is located at 3425 Bee Cave Rd. in Austin. For more information on their products, call Wyoma Craghead, (512)327-8326.


Apartments to Follow Green Builder Guidelines

The Gables at Central Park Apartments, currently under construction, will be the first Green Builder apartment complex in Austin. The Central Park project is on W. 38th St., adjacent to the Central Park retail center. Rick Craig, Vice-president of Gables Residential Trust, said, "making the Central Park project an environmentally superior one can only enhance its value and rentability."

The project will consist of 272 units and will include the following "green features": two ceiling fans in each unit, 12 SEER air conditioners, gas combo heaters, concrete containing 15% fly ash, engineered trusses, Hardiplank siding, low VOC paints, on-site recycling, excess construction waste donated to Habitat for Humanity, and water from a catchment pond used for landscape irrigation.


Green Builder Advertises for You

This past year, we have placed ads promoting the Green Builder Program and its members in the following publications.

Austin American-Statesman
American Builder Magazine
Builder Architect Magazine
Homefinder Magazine
Greater Austin Newcomers and Relocation Guide
Austin Business Journal
Product and Design Magazine
Groundbreaker Newsletter


Vapor Barriers: A Good or Bad Idea in the South?

As far back as anyone can remember, the common wisdom has held that in good building practice, a vapor barrier is necessary, and should be placed on the "warm-in-winter" side of the studs.

This maxim makes sense when the cold temperature is outside, and the excess moisture is inside. This fits the case of a winter day in the north, with the moisture created by people breathing, cooking, washing, etc. inside where it's warm. The vapor barrier (or vapor retarder*, a more precise term) just under the drywall keeps the water vapor-laden air from penetrating into the wall cavity, where it could condense on the cooler surfaces, causing rotting of the framing lumber and damage to the insulation.

But what about a climate that frequently has the reverse conditions? In the summer in Central Texas, the hot, humid air is outside, and the inside is cooled down and dehumidified by air conditioning. Under these conditions, wouldn't it make more sense to put the vapor barrier on the outside of the studs? But then again, we do get the occassional very cold day in winter here. How can we build for both conditions? Furthermore, what do our building codes require us to do?

The 1993 CABO Model Energy Code, adopted by the City of Austin in 1995, represents the combined wisdom of the four major code-writing bodies in the country. In Section 502.1.4, this code states that "the design shall not create conditions of accelerated deterioration from moisture condensation. In all frame walls and floors and ceilings not ventilated to allow moisture to escape, an approved vapor retarder having a maximum perm [permeability] rating of 1.0...shall be used on the warm-in-winter side of the thermal insulation."

This code allows two exceptions, however: "1. in construction where moisture or its freezing will not damage the materials, and 2. in hot and humid climate areas where the following conditions occur: 67 degrees F or higher wet-bulb temperature for 3,000 or more hours during the warmest six consecutive months of the year...." Exception 2 describes conditions in Austin.

It took so long for the code to make this exception because we really did not have a clear, scientific basis for prescribing other methods in a hot, humid climate until recently. Now the Department of Energy has completed computer modeling and controlled field tests in various sections of the country that ascertain which approach works best in each one.

Based on this research, Joe Lstiburek and John Carmondy have written the landmark Department of Energy publication, Moisture Control Handbook, New, Low-rise Residential Construction, published in 1991. Lstiburek and Carmondy show ten wall framing types appropriate for hot humid climates. Some have vapor retarders and some do not, depending on particular conditions, and whether it is preferrable for the wall to dry out to the inside of the building or to the outside.

In 1993, the Envelope Research Center at Oak Ridge National Laboratory published the results of its research on this topic. It concluded that both interior and exterior vapor retarders can lead to mold and mildew growth in wall cavities in the Gulf Coast region. Researchers stated: "For a cooling climate [where air conditioning is used more than heating], a permeable wall (without vapor retarding layers) was found to perform satisfactorily. During both winter and summer periods, moisture passed through the construction and did not accumulate significantly within the construction."

At a recent Green Builder seminar in Austin, Lstiburek pointed out that while water vapor is rarely a problem in a wall system without a vapor retarder, liquid water (i.e. rain) may be. He recommends that some kind of "drainage plane" be installed on the exterior of the studs in hot, humid climates. This could be simply 30-pound felt paper, or any low-permeability sheathing material or insulation board.

Interestingly, research also shows that many vinyl wallpapers and paints with low permeability cause moisture problems resulting in mold and mildew growth on the wall behind them. This moisture may also cause wallpaper to peel.

Besides the creation of condensation problems and the promotion of mold growth, another possible result of using a vapor retarder is that the house envelope may become tighter than the level recommended for good indoor air quality. In our mild climate, where mechanical ventilation systems are seldom installed, an air change rate of 0.35 air changes per hour is considered a minimum for good health. Homes with vapor retarders typically test below this rate.

In summary, reliable, scientific evidence on vapor retarders is now available and the code-writing bodies are in agreement: in a hot, humid climate, a drainage plane to keep out rain is advised, but a typically-installed (warm side-in-winter) vapor retarder is not required because it can cause more problems than it solves.

*Note that this article discusses vapor retarders, not to be confused with air retarders, used to decrease uncontrolled air-infiltration. Air retarders do not affect water vapor transfer.

For comments or question, call Doug Garrett at 499-3505


Green Builder Databases

The following are resources to help you find sustainable products, materials, and design assistance.

The Harris Directory
B.J. Harris
508 Jose St. #913
Santa Fe, NM 87501
Phone: (505)995-0337
Fax: (505)820-1911

Database on diskette which contains recycled content and resource efficient materials information.

REDI Guide (Resources for Environmental Design Index)
Iris Communications
258 East 10th Ave.
Suite E
Eugene, OR 97401
Phone: (800)346-0104

Both residential and commercial directories on diskette.

E-HouseTM
Environmental Building Consultants and Designers
312 A Jefferson Ave.
Cheltenham, PA 19012-2021
Phone:(215)663-1611

On diskette. Specifically geared for materials contributing to good indoor air quality.

The Environmental Home Database
Available through the LCRA
P.O. Box 2205-300
Austin, TX 78767-0220
Phone: (800)776-5272 x 7626
attn: Marcia Roberts, Good Cents, Environmental Home Program,
e-mail: marcia.roberts@lcra.org

This database lists environmentally friendly products, discusses environmental impacts of different building decisions, and lists books and periodical resources on "green building" practices as well as professional organizations and technical assistance available. LCRA has incorporated the Harris Directory, the National Park Services database, the City of Austin's Green Building Sourcebook, the Austin Environmental Directory, and local resources.

Eco Living Sourcebook
110 Linden St.
Oakland, CA 94607
Phone: (510)452-0500

On diskette, this database contains listings for more than 500 recycled content building and construction products from 80 U.S. companies. Includes descriptions, content percentages, standards, test results, specifications, distributors, and pictures.

National Park Service Sustainable Design and Construction Database
Attn: Sally Small
P. O. Box 25287
Denver, CO 80225
Phone: (303)969-2466

On diskette, product listing portion of database contains information about an estimated 1000 products. Can be searched by manufacturing plant location, CSI division, or product type. Products rated in 14 environmental factors. Also includes information about construction site recycling.

Woods of the World
Tree Talk Inc.
P.O. Box 426
431 Pine St.
Burlington, VT 05402
Phone: (802)863-6789

Diskette or CD-ROM interactive multimedia database of the world's wood species. Gives 85 fields of data on each species, including substitutes, and scans of colors and grains. The listing also provides information on managed sources and suppliers.

Other good references are:

City of Austin's Sustainable Building Sourcebook (400 + pages)
$25 from Green Builder Program
P.O. Box 1088
Austin, TX 78767

A technical and logistical guide covering practical issues associated with various green building choices.

AIA Environmental Resource Guide
AIA Order Dept.
9 Jay Gould Court
PO Box 753
Waldorf, MD 20604
Phone: (800)365-ARCH
Fax: (800)678-7102.

This comprehensive guide has recently been updated and is a good text for sustainable design as well as how to make material selections.

Guide to Resource Efficient Building Elements, Fifth Edition
Center for Resourceful Building Technology
P.O. Box 100
Missoula, MT 59806
Phone: (406)549-7678
Fax: (406)549-4100

Contains contact and product information for resource efficient and recycled material manufacturers producing everything from foundations to roofing.

McRecycle USA Registry Service
McDonald's Corporation Environmental Affairs,
Kroc Drive
Oak Brook, IL 60521
Phone: (800)220-3809

Updated continuously. Contains listings for more than 900 products made by 500 manufacturers, sorted by CSI divisions.

The Green Pages: The Contract Interior Designers' Guide to Environmentally Responsible Products and Materials
Andrew Fuston
45 East 25th Street
20th Floor
New York, NY 10010
Phone: (212)779-3365

Contains product listings from 536 manufacturers of environmentally responsible building materials, including recycled products.

The Resource Guide to Sustainable Landscapes and Gardens
Environmental Resources, Inc.
2041 East Hollywood Ave.
Salt Lake City, UT 84108-3148
Phone: (801)485-0280

This 368-page softcover book lists more than 1100 environmentally responsible landscaping materials, products, and information sources. Sorted by CSI division.

The Sustainable Design Resource Guide Colorado & the Western Mountain Region
Available from the Denver Chapter AIA
and Architects, Designers & Planners for Social Responsibility, Colorado Chapter
1526 15th
Denver, CO, 80202
Phone: (303)446-2266

CSI format offering sources of supply and specifying considerations.

Building Materials for the Environmentally Hypersensitive
Available from CMHC Publications
PO Box 3077
Markham, Ontario L3R 6G4
Phone: (800)668CMHC

This is a 238-page assessment of materials suitable for occupants with chemical sensitivities.

Environmental Outfitters TM
44 Crosby
New York, NY 10012
Phone: (800)238-5008

Customized lists of low-toxicity products carried by this firm.

IAQ Product Service Guide
$75 from Cutter Information Corp.
37 Broadway, Ste 1
Arlington, MA 02174
Phone: (800)888-8939

This comprehensive directory includes a section on "Interior Construction Products," plus air filters, cleaners, detection equipment, mitigation products, and consultants.


The Green Builder Newsletter is published by the City of Austin Green Builder Program, P.O. Box 1088, Austin, Texas 78767. Phone: (512) 499-3545, Fax: (512) 499-2859. Inquiries and articles are always welcome.

Editor: Jill Manlove Mayfield

Green Builder Staff
Doug Seiter--Manager
Susan Barnett
Laurence Doxsey
Doug Garrett
Perrie Hodge
Jill Mayfield
Pat Mazur
Mary McLeod


The City of Austin is committed to compliance with the Americans with Disabilities Act. This publication is available in alternative formats. Please call 499-2501 for information.

Planning, Environmental and Conservation Services Department
206 East 9th Street
Austin, Texas 78701


Back Issues available online: April 96


webmaster: Bill Christensen, InfiNet