Eco-Experts: Answers to Your Questions About Nontoxic Floor Coverings, Natural Detergents and Earthships Built From Recycled Tires

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Carol Venolia
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David Eisenberg
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Debra Lynn Dadd

Concrete flooring

I am trying to find sources for nontoxic floor coverings and know that you recommend bamboo, cork, or natural linoleum, but do you have any information on how healthy or nontoxic cement flooring is?

–Marsha Miller, via e-mail

David Eisenberg replies:

In general, cement (concrete) floors are inert and do not pose a toxicity risk as far as offgassing is concerned. For people extremely sensitive to chemicals, some admixtures in the concrete may be problematic. These are added for such things as controlling the workability or setting time of the concrete. And curing compounds, used to prevent rapid drying and cracking after concrete is poured, have been suggested as potentially problematic for highly sensitive people. It is usually possible to pour high-quality concrete floors without admixtures or curing compounds.

Greater concern about toxicity is related to the possible effects of finishes, such as stains, sealers, or waxes. If finishes are used, it is good to know what is in them and what health concerns are known about them.

Material Safety Data Sheets (MSDSs) should be available from the suppliers of most commercially available sealers and finishes. These provide important information about known health concerns, exposure levels, and proper safeguards for use. Adding pigments directly to the wet concrete before or just after it is poured and then troweling the surface to a hard, smooth finish usually makes it unnecessary to use any other finish.

Some people complain that standing or being on concrete for very long is hard on the feet, legs, and backs and therefore not generally healthy. Finally, though not a direct health effect, the production of Portland cement, the part of concrete that “cements” the aggregate (sand, gravel, and rock) together is quite energy intensive and contributes significant amounts of carbon dioxide to the atmosphere.

DAVID EISENBERG is co-founder and director of the Development Center for Appropriate Technology in Tucson, Arizona, and co-author of the best-selling book, The Straw Bale House (Chelsea Green, 1994).

Suds for duds

We own a high-efficiency (Bosch) washer and dryer. These increasingly popular front-end loading machines (now available in numerous brands) offer exceptionally low energy and water consumption. They require the use of low sudsing, high-efficiency detergents such as Tide HE. Regular detergents, even in reduced amounts, suds way too much! Because I see more and more articles suggesting that standard household cleaners and detergents may be responsible for adding to increased cancer rates, I would like to find a more healthful alternative. Can you recommend an environmentally friendly brand or product?

Karlen McBirney, Sandpoint, ID

Debra Lynn Dadd replies:

Many of the plant-based laundry products sold in natural food stores can be used in front-loading washers. In fact, a common complaint about plant-based laundry products in general is that they don’t suds as much as we are accustomed to with conventional detergents. Both Ecos liquid and powder laundry products ( can be used in high-efficiency washers and say so on the label. Ecover recommends using its laundry liquid in half the amount called for on the label, according to your water type. Soapworks ( says its soap-based laundry powder can be used in front loaders, “but use a little less.” In addition, your favorite natural laundry product may work fine. Give it a try, starting with half the recommended amount or less.

If you’d like to make your own washing powder, try this recipe (from “Seize the Laundry Day,” May/June 2000). Many of our readers have tried it and have been pleased with the results.

Washing Powder

16 cups baking soda
12 cups borax
8 cups grated castile or glycerin soap flakes
3 tablespoons lavender, lemon, or grapefruit essential oil

Combine baking soda, borax, and soap flakes (source: Sunfeather Natural Soap Company, (315) 265-3648, www., or grate your own from castile bar soap). Add essential oil and mix with a wire whisk. Use 1/8 cup of powder per load. This recipe makes enough powder to last a family of four one year.

DEBRA LYNN DADD is an internationally known expert on healthy home environments and author of Home, Safe Home (Putnam, 1997).

Pros and cons of Earthships

I would like to know if the Earthship building concept, using old tires, can create a toxic atmosphere when used in actual construction of a home. While the idea of recycling materials for dwellings is great, what does this choice do to the surrounding earth and the dwelling’s inhabitants?

–A Jyurovat, via e-mail

Carol Venolia replies:

The use of discarded tires to contain rammed earth in the walls of Earthships has spawned much debate about possible toxicity. Tires are indeed made of toxic substances, and they offgas when exposed to sunlight and/or heat. But the Earthship website ( says, “Tires are hazardous in piles, not Earthships,” and they back up their assertion with studies, professional opinions, and experience. Because the tires in Earthships are already largely offgassed and are surrounded by earth and cement plaster, there is little way for sunlight to degrade them or for offgassing to invade the living space. Furthermore, any contaminants are supposed to be diluted by high levels of natural ventilation. Among my chemically sensitive friends who’ve been inside Earthships, none have had negative reactions to them.

Yet many of my colleagues are uncomfortable about Earthships. Some don’t like the idea of living surrounded by toxic waste even if it is sealed up. Some are concerned about cracks in the plaster allowing offgassing into the space. One colleague has chemically sensitive friends who have reacted negatively to the air in Earthships. And some people prefer to live in a home with walls that “breathe.”

In summary, though the chances of being harmed by living in a well-constructed Earthship seem slim, there is some risk. You need to decide if it’s a risk you’re comfortable with. If you are chemically sensitive, you should spend time in several Earthships to find out if you react to them.

Also consider whether an Earthship is appropriate for your climate and site. Earthships are well suited to the desert Southwest, but the concept needs modification for other climates. There are many ways to incorporate recycled materials, passive solar heating, natural ventilation, earth sheltering, energy independence, and organic form into your home; the adventure is in finding the right strategies for your circumstances.

CAROL VENOLIA has designed homes of straw, earth, and wood, and consulted on the design of schools, healing centers, and eco-villages. Her book Healing Environments: Your Guide to Indoor Well-Being (Celestial Arts, 1988) looks at how our personal environments can increase our vitality by bringing us closer to our natural state.

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