November 16, 1999
by Tom Lent
Developing a small CoHousing community with a group of concerned fellow owner-developers provided me with a wonderful opportunity to try to soften the harsh environmental impact of standard construction practices. Starting in the design process and continuing through construction, we discovered many ways to maximize the use of environmentally sound materials and design. We also learned from several disappointments, as some of our dreams of doing the right thing were thwarted. Our failures were 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 do the basic work necessary to pull off this whole crazy project while also doing all the research we would like to have done to truly push the envelope on sustainable material use. In this article, I try to summarize many of the lessons learned - both from what we successfully accomplished and what we learned from what we failed to implement.
Our sustainability concerns started before construction with site preparation. We have adjusted the grading of our site to try to maximize opportunities for percolation of rain water before it runs off into the storm sewer system - not easy in an area with dense clay soils and not easy with engineers who get nervous with any solution that doesn't just move the water off site as rapidly as possible (ours wanted to plumb our down spouts directly into the storm drain system).
We salvaged and milled black 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). Getting this wood rough milled, dried sufficiently and finish milled in time for the construction time line, turned out to be a major headache and quite expensive. Acacia is very hard and the staircase will probably be very long lasting, but it was considerably more difficult to work with then the Douglas fir it replaced. An additional unexpected complication was that the sawdust from the acacia turned out to be as irritating an allergen for the carpenter as the infamous acacia pollen can be. Now that it is done, however, we have a very striking interior stairway due to the beautiful strong grain pattern of the acacia.
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 that didn=t cost us a penny (the new owner paid $5000 to the tree hauler). We 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. Unfortunately, this exploratory surgery resulted in a water line break that led to reshingling a section of house and cost us $1000 to repair.
Demolition provided many more opportunities to reuse and recycle. We salvaged lots of bricks, tile and lumber from the demolition process. The contractor separated most materials for recycling, such as wood and concrete and asphalt roofing material, during the initial heavy demolition phases of the project. This separation ended as the project went on and the weekly volume of debris went down. At that point it became harder to rationalize the space and expense of separation. Once we got to the finish stage, where lots of light fixtures, plumbing fixtures, appliances, cabinets and other things arrive on site in boxes, we started separating cardboard for recycling. Getting the message to all workers and subcontractors to separate the recyclables proved to be difficult. Constant dumpster diving was required and plenty of good recyclable materials escaped us despite our best efforts. Old sinks, toilets, windows and a water heater salvaged from the demolition got us enough exchange credit at the local salvage yard (Urban Ore) to obtain several windows and doors we needed.
Starting from the ground up, we used 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. Cost considerations drove us to use asphalt in our parking lot, but I would think hard and do more research before dumping all that toxic oil on our ground and into our air again.
Our mud sills (the wood that goes on top the concrete foundation) and much of the deck framing are wood treated with ACQ Preserve, a low toxic alternative to the usual highly toxic arsenic based (ACA or CCA) preservatives.
We searched hard for non toxic solutions to our termite problems in the existing units. We found a pest control company (Live Oak Structural) that specializes in low or no toxic measures to help us avoid the use of chemicals wherever possible and use the least toxic ones where unavoidable. They developed an innovative sand barrier application on the inside foundation walls to replace the usual chemical treatments. Installation is more expensive than pesticide spraying, but since it lasts indefinitely, it pays for itself by avoiding repeat applications of the pesticides in future years.
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 had not yet gone through certification testing for this earthquake zone. Maybe it will be by the time you are ready to use it.
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 weeks delay in our schedule at that point could have been disastrous.
Lesson learned: Put sustainable lumber into your specifications from the beginning to make sure that your contractor bids the job with it and has a cut list ready before the construction loan close. That way you will be able to place your order at the earliest possible time as soon as the money is committed and avoid the frustration we experienced. We couldn't do all we hoped to, but at least we are part of creating the demand for those who follow us. Soon it will be available dried off the shelf if enough of us ask for it.
We used certified sustainably harvested redwood for much of our decking and trim. I say much instead of all because this proved to be a supply challenge as well. Check the certification documentation from your supplier carefully and demand it up front early in the process. Many suppliers will say they have certified lumber, but that can mean many different things, often only that they plant as many trees as they clear cut. Only the Smart Wood or Scientific Certification Systems certifications mean that the wood really came from truly sustainably managed forestry operations that care for the long term health of the forest ecosystem. Lumber delivered for our first deck was claimed to be certified sustainable, but turned out only to be cut like all other timber, under weak state law guidelines. We managed to get the remainder of our decking in truly certified lumber by switching to a dealer (EcoTimber) who specializes in it, with the exception of some of the larger dimension items. It was easy to get 2X6s and 4X4s, while virtually impossible to get larger dimension lumber except by special order which, once again, we were out of time to do.
We also used finger jointed wood pieced together from smaller lengths wherever we could in places like trim and siding where there are not structural considerations and where the wood was to be painted instead of stained. Our architect worked hard to get the engineer to use wood efficiently and minimize overbuilding and improved the design considerably. We still ended up with a couple of beautiful but embarrassingly large beams that probably could have been replaced with engineered wood or other more minimalist solutions.
Our flooring is made from bamboo plank instead of wood in several units, from certified sustainably harvested machiche laminate floating floor in other units and from salvaged hardwood flooring in another. The carpet pad and floating floor pad are made from recycled materials (fabric for the carpet pad, old tires for the floating floor pad).
On the roofs we used fiberglass composite shingles, which are considerably less toxic than standard asphalt shingles.
We tried hard to specify materials that would have the least impact on the indoor air quality in addition to being otherwise environmentally desirable. In order to avoid radioactive materials, we installed photoelectric smoke detectors instead of the normal radiation based ones. We specified carpet made from wool with jute backing instead of plastics. We considered using carpet made from recycled plastic, but decided against it on account of the out gassing from plastic carpets (whether recycled or not) and due to the controversy over the environmental appropriateness of recycled plastic products. We avoided the use of particle board as much as we could afford due to its high formaldehyde off gassing, instead substituting solid wood and plywood in all cabinets wherever possible. We used zero VOC paints on the interiors (Benjamin-Moore's Pristine line). Several major paint manufacturers promise to have zero VOC exterior paints soon. We'll watch for them when we get to repainting. One finish we did not evaluate for environmental impact was stains and clear wood finishes. I certainly would try to improve that in future projects.
Another issue I would address early on next time is EMF (electromagnetic fields). We have put many of our electric supply lines underground that previously dangled across the property and hung right next to bedrooms, thereby reducing a significant source of EMF. However, the tradeoff is that we now have multiple meter boxes mounted on the sides of two houses to feed the others, producing a concentrated source of EMF for those houses. We may need to find a retrofit to shield these units as they are on bedroom walls where people will spend long hours sleeping nearby. We could have avoided this problem by locating the boxes on walls adjoining rooms that aren't occupied for as many hours each day, such as bathrooms or kitchens.
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 the job - 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 heating energy designs, meet or exceed the state standards for the moderate Bay Area with good insulation and efficient windows. We fully retrofitted insulation in all of the existing buildings at or beyond the level of energy efficiency required of the new buildings (R-19 in floors, R-13 in walls, R-30 in ceilings). I wish now that I had pushed harder to spend the extra money to thicken our new construction walls to get more insulation into them and to use low-e coated windows. There were challenges in getting even a good basic insulation job. It required very close supervision to get a quality installation job out of the subcontractor. Crews left large voids in some places and over packed the fiberglass in others in ways that would have cut the insulation effectiveness dramatically. Some problems could only be fixed by going back after the crews and redoing it myself. Particularly disturbing was the fact that the crews blowing insulation into existing walls apparently failed to understand basics about existing wall structures and left large areas uninsulated due to not identifying and working around fire blocking in the walls.
We designed the buildings with more glass area on the south side to capture solar heat, extra thermal mass (through the use of a thicker than normal 5/8" sheetrock, gypcrete or concrete floors and some tile floors) to absorb the solar heat and smaller window areas on the north to cut down heat losses. Overhangs are designed to shade summer sun and allow winter sun in. 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. The remainder use fan coil distribution systems that can be individually shut off for zoning control. Air conditioning is not an issue in the Bay Area with ocean breezes moderating temperatures throughout the summer. We have plumbing installed to the roof and strong south facing roofing structures to support future solar water heating options on all new units
We went the extra mile in conserving electricity and water as well. We designed for compact fluorescent lamps in all fixtures and are using water saving toilets, showerheads and faucets. In our common laundry, we installed horizontal axis washing machines to reduce our water consumption and water heating gas use. Of course, we also use solar clothes dryers.
The good news is that we were able to do some of this at little or no extra financial cost - in many cases just the cost of our time to research, find and evaluate the options - an important consideration in this project with serious price constraints. Some of these practices actually saved us money up front , such as grading for percolation instead of plumbing to storm drains, some of our salvage, recycling, the single water heater system, and finger jointed wood.
Some of the materials (such as the ACQ, certified redwood, zero VOC paint, machiche laminate floating floor and the recycled floating floor pad) did cost more, although mostly just 5-10% over the standard material (the machiche was considerably more expensive). Some of the energy efficient products, such as the compact fluorescent lamps and horizontal axis washing machines, cost far more than that over the alternative, but pay for themselves quickly in energy savings. Some of our efforts to reuse and recycle (milling our felled trees, reusing old cabinetry, etc.) became quite expensive in time and/or money.
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 developing permaculture plans for our post construction landscaping.
Do you want to improve the environmental impact your project? You can do far better than standard practice without going broke, but you will have to work for it. Start early and be very specific with your architect and your builder about the energy and resource efficient designs and materials you want to incorporate. Be ready to do lots of research and ask lots of questions. Don't assume that your design team or builder understand your desires or understand sustainable materials and design. Be persistent as well as clear. Don't be put off by your design professionals or builder telling you that "we will deal with that issue later in the process". Anything not specified pretty precisely very early on is likely to end up costing more money to add in later or to not to happen at all. With persistence, your efforts will be rewarded with a project that is much more friendly to the environment. Perhaps even more important, you will have educated your architect, contractor, subs and suppliers, making it that much easier for the next person to do the right thing.
The project is a Cohousing community in Berkeley, California with 14 houses clustered around a common house in which whole group dinners are cooked three to four nights a week. The project was finished in July 1997. All of the units are sold at this time, but if you would like information about our occasional tours and the waiting list, leave a message at 510-549-3749.
Information on cohousing books, magazines workshops, slide shows and other information about cohousing can be found at:
- http://www.cohousing.org on the world wide web, or
- Cohousing Network at PO Box 2586, Berkeley, CA 94702, or
- Cohousing Company (our architects) 510-549-9980
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 either in print or CD, send $35 to ADPSR, PO 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.
The 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 Intnl 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 Specialties 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 including framing, hardwoods, and all wood and bamboo flooring products (including pads from recycled tires) used here 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 suppliers.
Wool & other natural fiber carpets and recycled carpet pad are available from Hendrickson Naturlich Flooring in California at 707-824-0914.
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.
Energy & water efficient appliances are rated in the "Consumer Guide to Home Energy Savings" published by ACEEE in Berkeley at 510-549-9914. Oddly, they don't include the most efficient refrigerator (and also - by a long shot - the most expensive) on the market - the SunFrost from Arcata, California available from Real Goods in California at 800-762-7325 or at their retail outlet in Berkeley at 10th & Gilman.
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