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Ecology House Inc.
November, 1997


If you have comments or questions regarding Ecology House, please email us.



The drawing of the site plan is available as a separate file. Due to its size, it can take a long time to load.



The Table of Contents, continued for this section:
Materials to Avoid
Other Design Criteria
pages 8-18
Site and Floor Plans
Slab Insulation
Exterior Siding
Wall Assembly
Roof Assembly
Railings and Fences
Balcony Waterproofing
Mechanical Ventilation
Water Filtration







Ecology House planners knew from the beginning that the design of the building was only half of the equation. Equally important was maintaining a safe environment through careful, least-toxic property management and elimination of the use of scented and toxic materials by residents and maintenance personnel.

Ecology House residents comply with very restrictive rules regarding use of scented personal care products, laundry products, and household cleaners, smoking, burning candles, keeping animals, idling car engines, etc.

Individual tolerances to materials vary greatly among those with MCS. Therefore, agreement among residents on a single issue is difficult. Each property management decision must be thoroughly researched. One observer commented that each property maintenance task at Ecology House becomes a giant science project!







The following design criteria were developed by the Ecology House Design Committee. The criteria consist mostly of a list of materials, commonly used in California affordable housing construction, which should be avoided.



Materials to Avoid


  • onsite application of paint or sealers. Avoid materials which will need to be maintained by painting.
  • particle board and formaldehyde-bearing materials.
  • pressure-treated wood
  • glues and laminates
  • asphalt.
  • carpeting.
  • natural gas in living spaces.
  • fluorescent lighting.
  • exposed wood -- Minimize use of exterior plywood or use alternate method to establish lateral/seismic shear strength.

    Other Design Criteria


    • Use wiring techniques which minimize electromagnetic fields. Locate refrigerators, stoves, electric panels and electric motors to minimize the impact of electromagnetic fields and noise.
    • Install mechanical ventilation through the roof, with fans at roof level, not in the apartments.
    • Mechanically vent the attic with fans vented up through the roof and not at eaves or rakes.
    • Design for cross-ventilation in all occupied spaces, rather than air conditioning.
    • Beware of remanufactured materials. Most are less tolerable for persons with MCS because of added chemicals.
    • Use design features to discourage termites and other pests, since pesticides cannot be used.
    • Select landscape plantings which need no mowing, and never require fertilizers, herbicides, or pesticides.





Ecology House -- List of Special Design Features and Materials to
Accommodate Persons with Multiple Chemical Sensitivities


This list includes only features which are unusual for affordable HUD-financed rental housing construction in the San Francisco Bay Area. They were used in an attempt to make the building safer for persons with Multiple Chemical Sensitivities (MCS).


Site and Floor Plans


  1. The building was oriented to allow the almost-continual breezes in the neighborhood to flush air through the building.
  2. All units have ample cross ventilation. All bathrooms and kitchens have openable windows.
  3. The trash room is as remote as possible from the apartments.
  4. The only location where natural gas burns is in a separate mechanical room vented to the roof. (Please see heating section below.)
  5. Units surround a courtyard with concrete and tile benches. The courtyard provides a congenial outdoor gathering spot and provides cross ventilation for apartments.
  6. Parking is as remote as possible from the units.
  7. The site plan provides for concrete walks or patios or a 24" strip of pea gravel to separate the buildings from landscaping, in an effort to discourage termites and other insects and growth of molds. Standard California construction practice would call for pressure-treated mud sills, which are toxic for most persons with MCS. Ecology House uses no pressure-treated wood.
Result: Ventilation in the apartment units is good. However, the interior courtyard needs frequent cleaning because ambient dust blows in. Other pollutants, such as car exhausts, asphalt fumes, pesticides, also easily enter units, if windows are open.





Slab Insulation

Ecology House planners were concerned about the potential for mildew with a slab foundation and hydronic baseboard heat. Therefore, foam board was installed under the slab to insulate the slab and eliminate potential for condensation and mold. Insulfoam Polystyrene foam board (Western Insulfoam Corporation) was laid down under the slab and along the side of the footings up to the sill.

Result: The building is easy to heat and cool. No mildew has formed.






Cost constraints require asphalt parking and driveway paving in HUD-financed housing. Since asphalt is very toxic to persons with MCS on hot summer days, no asphalt was used. The parking lot is paved with concrete. The concrete mix for all concrete (parking lot, walkways, courtyard, and balconies) contained no additives.

Result: No problems tolerating the concrete. More minor cracking than would be expected if additives had been used.





Exterior Siding

To reduce construction cost, most California affordable housing uses plywood, hardboard, wood shingle, or stucco siding. Ecology House uses preformed metal siding with factory-baked enamel paint. Integral-color stucco was also used. Both materials were selected because they will not need to be repainted. For residents with MCS, new exterior paint can be life-threatening when applied and long after, until the paint totally outgasses.

The ship lap metal siding and stucco were also selected because they harmonize well with the surrounding neighborhood. The metal siding is fabricated to look like the wood siding used on the upscale, market-rate homes surrounding Ecology House.

The metal siding we selected came with few trim pieces. Powder-coated aluminum was fabricated for window trim. For roof facia, downspouts, and water table trim, galvanized sheet metal was painted on site with Sherwin Williams System 4000. This Sherman Williams paint was the only paint applied on site. Our pre-tests indicated that the SW paint offgassed quickly. Since the paint was applied at least 90 days before residents moved in, it seemed acceptable.

Result: Metal siding is now tolerated by residents. Some said that the siding had a slight odor during the first few months of occupancy, and this may have contributed to some of the problems that some residents initially experienced. However, it did not seem to cause major problems, probably because it is outside.

The stucco seems well tolerated now. However, when stucco is freshly applied to repair cracks, it can be problematic for some individuals with MCS.







  1. Walls were framed with Douglas Fir. We researched the possibility of using steel studs but had to reject steel because of the extra cost.


  2. Structural steel posts and beams used in the community room were not primed.




Wall Assembly


  1. Two layers of Tyvek building paper were installed over gypsum sheathing. We used Tyvek to avoid asphaltic building paper on all walls.
  2. Plywood sheathing was nailed to the studs. On end walls without windows and on interior party walls, 1 x 6 diagonal sheathing was used instead of plywood. We very much wanted to completely avoid plywood. However, the Ecology House site is in Seismic Zone 4. Given our cost and time constraints, use of exterior plywood was the only way we could meet building code shear strength standards in Seismic Zone 4.
  3. Walls and ceilings were insulated with Insul-safe III (a fiber glass blown-in insulation) manufactured by Certainteed. Cost constraints and concerns about moisture absorption, which might foster mold growth, precluded use of a non-fiber glass product.
  4. An aluminum foil vapor barrier (R+ from Innovative Energy) was stapled to wall and ceiling studs behind the interior plaster board to seal all interior spaces from offgassing insulation, wood studs and plywood. Foil edges were sealed with Polyken aluminum foil tape. The tape adhesive has a strong odor when the protective film is initially stripped off. However, after it is stuck to the foil, it seems tolerable to persons with MCS.
  5. Rather than textured and painted drywall, U.S. Gypsum's Imperial Plaster system was used for all interior areas except bathrooms and the airing room. The Imperial system includes a gypsum plaster board (Imperial Board) with two coats of plaster over the board. A traditional lath and 3-coat plaster system was used for wet areas. No paint or sealer was applied to interior walls or ceilings.

Information from the Imperial System manufacturer, USG Corporation, indicates that 99.6% of the weight of the plaster base board is comprised of plaster of paris, water, recycled paper (cellulose) gypsum and starch. Recycled papers (a mixture of kraft, magazines, newsprint, mixed paper, and corrugated kraft paper) make up the back and face of the gypsum board, and some recycled paper fiber is added to the core of the board. Gypsum used in the gypsum wallboard in Ecology House was mined in its natural state and is not recycled.

Ingredients in the basecoat and finish plasters used in the Imperial System are primarily (99.7% for basecoat and 99.2% for finish) plaster of paris, silica sand, and calcium sulfate.

Minor ingredients include several chemical additives which comprise .4% of the weight of the plaster base board, .3% of the basecoat and .8% of the finish plaster. Three of these minor ingredients include aromatic naphtha, glutaraldehyde, and formaldehyde polymer. USG Corporation bakes the wallboard at temperatures between 425 and 480 degrees during the last 30 to 45 minutes of manufacture.

Murco M100 taping compound was used exclusively throughout the building.

Result: It's difficult to determine whether the Tyvek building paper was a good choice. Some type of moisture protection must be used on the walls, and Tyvek seemed less toxic than asphalt. However, some persons with MCS find Tyvek toxic.

The foil vapor barrier seems to have successfully blocked offgassing insulation and wood resins from the units. However, the foil was not tightly sealed around some electrical receptacle boxes. After occupancy the Contractor caulked around the electrical boxes (between the edge of the box and the plaster board) for residents who requested that the boxes be sealed.

The Imperial plaster seems to have outgassed significantly since initial occupancy. The initial distinct gypsum odor has dissipated. Over time, however, the plaster has produced mixed results. Some residents tolerate the plaster well and like the unpainted and unsealed plaster. Other residents (about half) do not tolerate the Imperial plaster well.

After installation, the plaster dried with a very dusty surface. After a thorough vacuuming, the dust was noticeably reduced. However, the surface of the unsealed plaster still continues to shed a minute amount of fine dust. Some residents frequently wipe and vacuum the walls to eliminate the dust. The cleaning burden must be weighed against the benefit of a paint-free interior surface. Those with upper respiratory sensitivity may not be able to live at Ecology House without sealing, air purification, or other precautions.

Unsealed plaster is more porous than a painted or sealed surface. The unsealed plaster may have absorbed paint fumes from the cabinets and doors in the units and may have been slowly outgassing those paint chemicals. It's difficult to know the significance of such absorption and subsequent outgassing.

On an experimental basis we applied four coats of Crystal Aire sealer (manufactured by Pace Chem) to the walls and ceiling in one unit. The resident of that unit reports that, after outgassing, the sealer improved tolerability. After spending time in the sealed unit, some residents are now deciding whether they, too, would like to have sealer applied in their units. Ecology House, Inc. has sought additional outside grant funds to pay the $1,000 per unit cost to apply four coats of sealer.

It's impossible to determine whether Ecology House residents tolerate the Murco taping compound, since the taping compound is now under the plaster.





Roof Assembly

Standard California affordable housing often uses composition roof shingles. Hardishake fiber cement shingles were chosen for Ecology House because they contain no asphalt or fiberglass, are guaranteed for 50 years, and are non-combustible. Plywood roof sheathing was covered with asphalt-saturated roofing felt. We reluctantly agreed to asphalt roofing felt because Hardishake requires asphalt-saturated underlayment to guarantee the roof.

Result: The asphalt-saturated felt is sandwiched by the shingles and plywood and does not seem to have caused difficulties for residents. The asphalt toxicity is also mitigated by powered roof vents and by persistent breezes.





Railings and Fences

To avoid the need for frequent repainting of galvanized rails, balcony and stair railings are fabricated with powder-coated aluminum. Fences adjacent to the units, patios, courtyard, and entry ways are also powder-coated aluminum. Cost constraints prevented use of aluminum for all fencing. Perimeter fencing is constructed with untreated redwood.

Result: Excellent tolerability. The powder-coat finish seems to be nearly inert and should never need paint. One resident initially had problems with the redwood fence but now, after many months, tolerates it well.





Balcony Waterproofing

Selection of a waterproofing material for the balconies was problematic. We wanted to avoid asphaltic materials (such as Bituthen) and toxic elastomeric sealers and at the same time create a watertight seal.

Self-adhesive Polyken 660 waterproofing membrane (manufactured by Polyken technologies) was laid under a polystryene protection board (AMOCOR-PB4 manufactured by Amoco). The protection board was covered with 2" of lightweight concrete (without additives). The Polyken membrane sample had a strong odor when sniffed. However, sniff testers found it reasonably tolerable, especially in light of alternative materials.

Result: Balcony waterproofing appears effective. Residents have not reported problems with tolerability.






In California, standard affordable garden apartments are generally heated with individual gas-fired, forced air furnaces. Forced air heating systems are problematic for those with MCS due to accumulated dirt and bacteria in the ducting and the toxicity of natural gas. Ecology House used hydronic baseboard convector units. Hot water travels through a closed-loop piping system connected to a single gas-fired boiler in a separate mechanical room, vented to the roof of the mechanical room. The heater housings are steel with a factory-baked enamel finish.

Result: The hydronic system is energy efficient, and energy savings are enhanced by the foil vapor barrier. At the time of initial occupancy some residents found the convectors difficult to tolerate, probably because the factory-baked finish still had not sufficiently outgassed. The housings now appear to be well-tolerated. The heat is comfortable for residents.

To avoid problems with convectors, we would have preferred to use radiant heat in the floor. Unfortunately, we had to reject radiant heat because of its significantly higher cost.





Mechanical Ventilation

As discussed above, all apartments have ample cross ventilation. Bathrooms and kitchens have operable windows. To protect residents from other residents' cooking odors and to mitigate against mold, kitchen and bathroom are mechanically vented to the roof. To mitigate against the noise and electromagnetic fields generated by the vent fans, fans motors are located on the roof.

To avoid build-up of gasses from attic insulation, lumber, and other materials during hot weather, attics are also ventilated by powerful fans vented through the roof.

Result: After occupancy it took some time to fix installation problems with the kitchen and bathroom fans. Noise from vibrating ductwork and defective motors rendered some of the fans unusable. Since those installation problems have been fixed, the fans have been better tolerated and are an important ventilation component for most residents.

Providing adequate ventilation issue is difficult in this small, two-story apartment building. Ecology House avoided air conditioning because it creates problems for many persons with MCS. However, some form of mechanical ventilation is essential because windows cannot always be kept open. Because many persons with MCS are extremely noise sensitive, designers must be very careful with ductwork design and selection of fans to minimize noise.

There have been functional problems with fans which vent the attic space, and some of the fans have not been operational. The lack of functioning attic fans may have contributed to problems some residents had in tolerating their units. More recently attic fans have functioned properly, and at least one resident reports markedly improved air quality in her unit.





Second floors are underlaid with 1 x 6 wood sheathing, rather than particle board. (The ground floor is the concrete slab.) Rather than carpeting and sheet vinyl, which is standard for affordable housing, a glazed quarry tile floor was installed in a full mortar set with Portland cement without additives. No thin-set was used for any wall or floor tiles.

Grey Portland cement grout with sand was used. The grout was not sealed due to concerns about toxicity of grout sealers. To mitigate against the potential for mold on unsealed grout, bathrooms were ventilated with powerful fans and openable windows.

Result: The tile is appreciated by all residents. Since the grout is unsealed, the sand in the grout tends to rub loose and leave grit on the floor. Sweeping, vacuuming, or mopping removes the loose sand. However, it is an annoyance. Other builders of MCS-accessible housing report having little or no loose sand if the grout is more slowly wet-cured.






Plywood or particle board cabinets with plastic laminate countertops are the materials most frequently used in affordable housing construction and are also extremely problematic for persons with MCS. Ecology House chose steel cabinets with factory-baked enamel finish. Countertops and sinks are stainless steel. Cabinets and sinks are adaptable for persons who use wheelchairs.

Result: The factory-baked-enamel finish on the steel cabinets has been problematic. The cabinets arrived with a paint odor not well tolerated by residents, and have been slow to outgas. When the cabinets were delivered, several discussions occurred between the Contractor, Architect, Ecology House, Inc. and the cabinet manufacturer (Cervitor Kitchens, Inc.) At that time the Owner concluded that the cabinets met specifications, even though they "stunk", and the Owner had no legal recourse against Cervitor. Investigation also indicated that Cervitor's length of time and temperature for baking the paint were similar to those used by another manufacturer whose bid was much higher.

After two years of occupancy, outgassing seems to have improved tolerability for most residents. However, the painted finish has peeled in some areas, especially under the sink. Cabinet bottoms under the sink on which paint has peeled are being replaced with stainless steel pans.

Stainless steel cabinets would have been a better solution, although they are considerably more expensive. Powder-coated paint finishes, which are baked at far higher temperatures than enamel paints, likely would have produced a much more tolerable surface. However, powder-coated cabinets are rare and extremely expensive.






Ecology House planners knew that most caulking is toxic to persons with MCS. GE 100% Silicone Caulk was reported to be well tolerated by most of those with MCS, and it was used exclusively for all caulking in the building. Result: The GE 100% Silicone Caulk is well tolerated by residents after it dries and hardens.. Before the caulk is used for property maintenance, residents are notified so that they can leave if they do not tolerate the caulk while it is applied and dries.






Milgard dual-glazed, aluminum-frame, sliding windows and patio doors were used with aluminum screens. To avoid standard, toxic window caulking, windows were special ordered with silicone caulking (at extra cost).

Ceramic tile was set on the window sills to make the sills easier to keep clean and dry to avoid mildew and to avoid problems of the sills being aged by sunlight. Window coverings are aluminum mini-blinds with baked-enamel finish. To avoid a painted surface on the blinds we attempted to locate unpainted metal blinds and could not find any.

Result: Windows effectively prevent air and water infiltration. Mini-blinds are well-tolerated.






Interior and exterior doors and frames are steel. Door cores are insulated with a foam board insulation, rather than fiberglass or mineral wool. Doors were factory-primed and spray-painted off site with Dupont Cronar, a fast-drying automobile paint.

Door frames are steel with a factory-baked polyester paint (manufactured by Timely).

Closet doors are also baked enamel bifold steel doors. Closet shelves are also metal with a factory-baked enamel finish.

Result: A few residents did not tolerate interior doors, closet doors and shelves immediately after occupancy. Doors now seem to have offgassed sufficiently to make them tolerable to all residents.

Using prefinished door frames and painting off-site required touch-up paint on site after installation but prior to occupancy. Because of concerns about lingering toxicity of paint on site, especially paint on doors, the contractor was asked to dab on only enough touch-up paint to cover damage. Consequently, some of the touch-up paint is obvious. However, the tiny amount of touch-up paint caused no apparent toxicity problems.






The following wiring techniques were used to minimize electromagnetic fields:

  1. No fluorescent lighting was used. The City Building Official allowed incandescent lighting in kitchens and baths, even though California's Energy Code for new construction requires fluorescent lighting in kitchens and baths.
  2. Refrigerators were located to minimize electromagnetic field exposure to adjacent units.
  3. Main wiring runs were done with Aluminum Romex. Branch circuit wiring was done with copper. All wiring was with three conductor, twisted pairs.
  4. All power was distributed through the attic and dropped down to unit panels in conduit.
  5. Power was distributed from the meter to the elevator mechanical room and laundry room in continuous rigid conduit underground.
  6. Metal EMF shielding (a mu-metal type alloy) was installed in the walls behind electrical meters in the electrical room and on the second floor floors above the first floor ceiling fans.

Result: EMF testing after the building was occupied indicated some standard wiring problems which were corrected by the contractor. After these corrections were made, special EMF design features have kept EMFs generated by power in the building at minimal levels. With the exception of temporary increases in EMF levels near appliances while appliances are in use, the EMF levels in the building are close to the ambient EMF levels measured on site before the building was constructed. (.6 to 2.6 milliGauss)

As discussed above, the Ecology House site is near high voltage lines. Potential residents with extreme sensitivity to EMFs may not be able to live in Ecology House.





Water Filtration

Ecology House installed a Filtrine whole-house water filtration system in the mechanical room. The filter purifies all domestic water, including water used for showers and toilets, before water comes to units. The Filtrine filter removes chloramine added to the water supply by the water district as well as particulates.

Result: The filter has functioned well and seems appreciated by all residents. A few residents have added their own point-of-use filters in the kitchen for drinking water. The whole-house filter is expensive for Ecology House to maintain, since the carbon in the large tank must be replaced once a year.






Ecology House used several special landscaping features which are unusual for affordable rental housing in California. In addition to concerns about pollen, flower-scent, mold, and insects, we also had to comply with local water district regulations regarding drought-resistant planting and water-efficient irrigation. Special landscaping features are:

  1. To avoid spray irrigation using chlorinated or recycled water, drip irrigation was used exclusively. Plantings are irrigated by a grid of underground drip tubing.
  2. Plant selection was constrained by several criteria:
    -- fragrance-free
    -- very low pollen
    -- strong, not needing fertilizer
    -- pest resistant
    -- drought-resistant
    -- tolerant of existing soils
  3. Pea gravel was used for mulch, rather than Redwood bark, since many persons with MCS do not tolerate Redwood.
  4. A 24-inch gravel strip separates the building from plantings in an attempt to keep out termites and insects and to keep dampness away from the walls and foundation.
  5. A less-toxic soil amendment mix (a mixture of fir bark, poultry manure, iron sulfate) was used to mitigate an existing alkaline soil condition.

Result: Ecology House landscaping has done well and is tolerated by residents. No fertilizers, pesticides, or herbicides have been used on site, since construction began. Irrigation has functioned well.




# # #


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