sustainable materials and design
From: Tom Lent (
Date: Mon, 4 Nov 1996 22:36:17 -0600
Hereis the latest update of my writeup (those of you on cohousing-l saw an
earlier version of this a month or two ago). Use and replicate it as you see
fit (not for profit and with proper attribution, of course):

Successes and failures lessons learned
November 1, 1996
by Tom Lent

It has been a priority to find ways to maximize our use of environmentally
sound materials and design in this project. We have had several successes
and several disappointments as we have succeeded in including some elements
and not others. Our failures are in part due to the nature of the state of
the art, in part to budget limitations (we are working under affordable
housing price guidelines as well as our own pocketbook restrictions) and in
part to our own lack of time and energy to pull off this whole crazy project
and do all the research we would like to do to push the envelope on
sustainable material use.

Our sustainability concerns started before construction with the site prep
and demolition. We salvaged and milled the acacia trees that we had to cut
down (they were nearing the end of their life, developing serious cracks and
crown root rot. and starting to come down of their own accord). We plan to
use the lumber for interior stairways. 

A large palm tree that needed to be removed was transplanted to a new home -
a spectacular process involving a large crane hauling the gigantic 40' tree
over a house and a set of power lines. We also saved a redwood that we had
been told would have to come down because of its proximity to a house.
Digging to explore its root structure allowed us to determine that it was
coexisting with the house satisfactorily. It also resulted in a water line
break that led to reshingling a section of house and cost us a total of
$1000 to repair. 

We salvaged lots of bricks, tile and lumber from the demolition process. The
contractor source separated most of the wood and concrete and asphalt
roofing material for recycling. Old sinks, toilets, windows and a water
heater saved from the demolition got us enough exchange credit at the local
salvage yard to obtain several windows and doors we needed. We designed our
site drainage to percolate as much rainwater back in to the ground as
possible rather than sending it in to the storm drain.

Starting from the ground up, we are using concrete with a 15% mixture of fly
ash - a recycled waste product from coal fired power plants - replacing some
of the energy intensive cement. We'd rather not have the coal fired power
plants, but if they must burn the coal, at least we can make good use of the
waste. In addition, the fly ash also makes the concrete a stronger and more
workable product.  

Our mud sills (the wood that goes directly on top the concrete foundation)
will be treated with "ACQ Preserve", an alternative to the usual
copper-arsenic (ACA or CCA) preservatives. 

We investigated the possibility of using straw bale construction but
returned to traditional stick framing because of severe space constraints in
our urban infill situation. We could ill afford to give up the 100 square
feet or so that the thick bale walls would occupy in each unit.
Additionally, we needed to build two story buildings to get the most out of
our space. Since Berkeley had yet to approve a one story bale house,
starting with a two story house was too large a leap. We will be using straw
bale construction for our sound wall at the end of our property that fronts
a noisy busy street. We also investigated straw panel options, but could
find no manufacturers that were actually in production at the time we were
completing our design. We came close to using a product called Thermoply for
shear sheathing made of recycled cardboard covered with foil, but it has not
yet gone through certification testing for this earthquake zone. Maybe next
Turning to stick framing we hoped to use sustainably harvested wood for the
framing and sheathing, but during the planning stages of the project, we
could find sources for neither. As we started construction we found plywood
for sheathing was still not available at all, but Douglas Fir for framing -
while not available predried off the shelf - could  be purchased milled to
order and delivered green. Alas, since we didn't have time to store it
ourselves to dry, we could have serious moisture problems. This could mean
problems with warping wood and popping nails down the road. Hem fir was
available kiln dried, but still had long lead time (4 weeks) for delivery.
By the time we discovered this availability, it was too late. We were under
construction, rushing to beat the winter rains and even a couple of week
delay in our schedule at that point could have been disastrous. Lesson
learned: Try hard to get your lumber list together before the construction
loan close so you can place your order at the earliest possible time as soon
as the money is committed. Oh well, as Katie says, at least we are part of
creating the demand for those who will follow us. Some day soon it will be
available dried off the shelf if enough of us request it.

We will use certified sustainably harvested redwood for the decking. We are
using carpet either made from recycled materials or from wool with jute
backing. The carpet pad is made from recycled material.  Our flooring is
made from bamboo instead of wood in all units except one in which we are
using hardwood flooring salvaged from another older unit. On the roof we
will use fiberglass composite shingles, much less toxic than standard
asphalt shingles. We are using paints with no VOCs inside and are
investigating the use of recycled paints on the outside. 

We wanted to avoid using PVC in the plumbing due to the toxic nature of its
production and disposal and concerns about its impact on water quality. We
ended up splitting - spending the extra money for copper for the water
service work, but resorting to PVC (instead of clay) for our sewer work for
price and resilience reasons. 

Our energy designs, both in heating and in lighting far exceeds the state
standards with good insulation and efficient windows, including fully
retrofitting all of the existing buildings to the same level of energy
efficiency required of the new buildings. We designed the buildings with
more glass area on the south side to capture solar heat, extra thermal mass
(through the use of thicker sheetrock) to absorb the solar heat and smaller
window areas on the north to cut down heat losses. Heating efficiency is
increased in our design by using a single water heater in each duplex to
supply all space heat and hot water for both units. Three of the new units
use radiant slab system to deliver space heat.

We are trying to go the extra mile in conserving electricity and water as
well. We are designing with compact fluorescent lights wherever possible and
using water saving toilets, showerheads and faucets. We will have plumbing
installed to the roof and strong south facing roofing structures to support
future solar water heating options on all new units. We are using
photoelectric smoke detectors instead of radioactive ones

The best news is that we are doing all of this at little or no extra
financial cost - in most cases just the cost of our time to research, find
and evaluate the options, an important consideration in this project with
serious price constraints.

Of course, the project inherently has positive environmental impacts beyond
these design and materials issues. As urban infill near downtown Berkeley
and on bus and subway lines to downtown San Francisco, we are providing more
housing that is walking and mass transit friendly. By our community
orientation (common meals, shared child care, group social activities), we
cut our needs to drive and to own more redundant appliances (like washing
machines) dramatically. We recycle every material we can. Living in
community makes it easier to pool our resources to handle the materials that
are not picked up at curbside. We compost all of our food waste for use in
our gardens and are exploring permaculture options for our post construction

For more info about how to join our community, contact us at 510/549-3749.
To chat with me about sustainable design and materials, e-mail me via
CoHousing-l or directly at "tlent [at]".


My bible and yellow pages for sustainable construction materials was the
Architectural Resource Guide, prepared by members of the Northern California
ADPSR (Architects, Designers and Planners for Social Responsibility). It
includes excellent descriptions of the pros and cons of different approaches
as well as extensive regional and national contact information to reach
manufacturers and distributors of the materials. To order a copy, send $15
($12 for the book plus $3 shipping and handling) to ADPSR, P.O.Box 9126,
Berkeley, CA 94709-0126. 

Also very useful are some of the computer databases of sustainable
materials, such as the Sourcebook from EcoLiving International in California
at 510-452-0500. Energy Efficiency and Renewable Energy Clearinghouse is a
good toll free source of information on energy efficient design at
800-DOE-EREC sponsored by your tax dollars.

Fly Ash should be available through RediMix and other local concrete
distributors. If they are not familiar with it, contact Pozzolanic
International in Washington at 800-416-5171 or Mineral Specialties in
Montana at 406-656-2334.

ACQ Preserve treated wood should be available through local lumber yards.
For help finding a local distributor, contact Chemical Specialities Inc., in
North Carolina at 800-421-8661.

Straw Bale information is available from Out On Bale in Arizona at 520-624-1673.

Sustainably harvested wood is available through EcoTimber in Berkeley at
510-549-3000 and a growing number of other suppliers. Ask your local lumber
yards first. If you can't find a source of certified lumber in your area
check with the certifiers: Rainforest Alliance in New York at 212-677-1900
and Scientific Certification Systems in California at 510-832-1415.

Fiberglass composite shingles should be available through local roofing
Recycled plastic carpet is manufactured by Shaw Industries in Georgia at
800-441-7429. Call for distributors. 

Wool & other natural fiber carpets are available from Hendrickson Naturlich
Flooring in California at 707-824-0914.

Bamboo flooring is available in the Bay area through the Berkeley Design
Center at 510/652-6064 here in Berkeley and Smith & Fong at 415-285-8230 in
South San Francisco.

Recycled paint is made by E-Coat Recycled Paint Products in California at
916-920-0550 and distributed by Kelly-Moore.

Photoelectric smoke detectors are made by BRK Electronics, model 2839.
Tom Lent * 2220 Sacramento St * Berkeley, CA 94702-1907
           email: tlent [at] * phone: 510/845-5243

Results generated by Tiger Technologies Web hosting using MHonArc.