My husband and I are interested in further insulating our attic and insulating our floor/crawl space. We want something breathable and nontoxic. We are concerned about the standard fiberglass.
—Sarah Carson, via e-mail
Believe it or not, fiberglass insulation is relatively natural. It's made from silica sand and as much as 30 percent recycled glass. What's more, it's inexpensive, resistant to mold, and indigestible to insects. However, the microscopic slivers of glass irritate uncovered skin, and greater exposure to the particles can lead to permanent respiratory ailments. Some researchers suggest it can induce cancer. In addition, some batts contain formaldehyde-based binders that may outgas after installation.
To address the particle problem, all the major manufacturers now offer sealed batts. The perforated polyethylene sheeting controls loose particles and doubles as a vapor barrier. To solve the formaldehyde problem, Johns Mansville now uses a nontoxic acrylic binder. Owens Corning has developed a product that binds fibers together without chemicals.
If you're still concerned about fiberglass, there are other options. Mineral wool insulation is similar to fiberglass, but the fibers are derived from iron-ore blast furnace waste. Although heavier and more expensive than fiberglass, mineral wool is more moisture-resistant and maintains its insulative properties when wet. During handling, however, small pieces can break loose, which raises health concerns similar to fiberglass.
Made from recycled newspaper, cellulose insulation is not only cheaper but also provides more insulation per inch than standard fiberglass. Cellulose is available as blow-in or loose-fill insulation. Unfortunately, cellulose insulation also contains flame retardants and binders and may contain dyes, synthetic resins, gums, varnishes, and solvents that are the result of using recycled newspaper. Although it has not been determined to cause a health risk, blowing in cellulose is dusty work. People who cannot tolerate the odor of a fresh newspaper should not overexpose themselves during installation. Once installed, cellulose sometimes settles (leaving uninsulated pockets in your walls) and loses efficiency if it gets wet. If allowed to remain damp, cellulose can harbor mold.
Cotton is possibly the safest material for both the installer and home occupants. Available in batts or loose-fill, it costs about twice as much as fiberglass. But it's not perfect and conventional cotton is also one of the most chemically demanding crops in the United States.
Whatever insulation you choose, it must not be "breathable" if you want it to do its job. Insulation works by trapping air between the inside and outside of your house. If air were allowed to freely pass through the walls, the interior temperature would soon match the temperature of the outside air. What's more, when warm, moist air from inside your home leaks out, water vapor will condense inside your walls. This can lead to a host of water-related problems, including deteriorated insulation and mold. The best way to avoid this is to install a vapor barrier on the wall&s warm side. Polyethylene sheeting is typically used with unfaced batts, but if you&re concerned about potential outgassing, you can use paper-faced batts.
Joe Hurst-Wajszczuk has been actively involved in home improvement, both as a writer and carpenter, for more than a decade. He edited Ask the Family Handyman (Readers Digest, 1999) and revised Wiring a House (Taunton Press, 2002).
I am restoring a 1940s home with steel casement windows. I want to remove the existing paint inside some of the windows and leave the steel surfaces unpainted. I need to use something to prevent rust. Any ideas?
—Gayle Comstock, via e-mail
Check out Fuhr International Specialty Paint & Wood Coatings, a Winigan, Missouri, business that handles nontoxic sealers. For your project, the company recommends DTM #1055, a low-VOC, water-based direct-to-metal coating formulated for use on metal surfaces. Available in gloss, semi-gloss, and satin finishes, it can be used as a primer and a finish product.
Water-based metal sealers have lower levels of volatile organic chemicals (VOCs) than their solvent-based counterparts. They can cause metal surfaces to rust, however, so Fuhr has added a flash rust inhibitor to hold off the oxidation process.
Contact Fuhr International, (800) 558-7437, to order and obtain a full product data and specification sheet.
Beth Scott is a member of Associates III, a Denver-based custom interior design firm that provides research, design, and specifications for architectural fixed finishes as well as design and procurement of furnishings.
Pooper-scoopers and composter
What is the best eco-friendly way to dispose of dog waste? We have three large dogs and are trying to find an alternative to just throwing it in the garbage.
—Gia States, via e-mail
Dog excrement contains no known potential disease pathogens communicable to humans, so there are alternatives to discarding it with household rubbish. (Cat excrement, on the other hand, can cause toxoplasmosis, a disease that affects the nervous system.)
Where the soil is dry and there is little risk of polluting groundwater, dog excrement can be trenched under a few inches of soil in your yard or elsewhere to be stabilized by beneficial bacteria, and its nutrients used by plants (preferably non-edible plants, just to be safe).
Composting is another option. Consider using or making a composter that is more contained and less accessible to rodents and insects. Get a fifty-gallon and a thirty-gallon plastic trash bin (or any other two sizes -the key is that one fits inside the other with at least two inches of space around it). Fill the bottom of the larger bin with four inches of sawdust, packed shredded paper, or soil-less growing media (found at nurseries). The smaller bin is your dog excrement receptacle. Drill many half-inch holes in the sides and bottom and place it inside the larger bin. The holes expose the sides of the composting excrement to air, which fast-acting composting bacteria need. Drill about five half-inch holes around the side of the outer bin or one large hole (three inches in diameter) and cover it with insect screening. Every week or so, you can add two cups of water and sawdust, some brown (not green) grass clippings, or a handful of finished compost to the smaller bin, and give it a toss with a spading fork or a hoe.
When it's full, build another two-bucket composter system of the same design. When that second composter fills, you can empty the contents of the first composter, which should be safely stabilized by then. Trench the compost under the soil around flowers and shrubs.
City dwellers who must pick up after their dogs in public places might consider bringing the waste home in a piece of newspaper or biodegradable plastic or cornstarch bags (often available at your natural foods store or from BioBag, 800-233-8438), which can be thrown into the composter along with the contents.
Carol Steinfeld is co-author of The Composting Toilet System Book (Chelsea Green, 2000) and conducts workshops on composting and composting toilets.