When specifying healthy building materials, use the following as a guide. Remember to read product labels and study material safety data sheets (MSDS) to find out exactly what is in a product before you buy it. Don’t assume the government is protecting you from harmful products or that the builder is representing your interests. In fact, government can barely keep up with labeling. It’s up to you to be an informed consumer.
Through our 40 plus years as a carpenter/builder we have come to really like building with softwoods. SPF is easy to work with, plentiful, and less expensive than other materials; hardwoods or steel.
However, the natural resins in softwood lumber, spruce/pine/fir or known as SPF, outgas terpenes and other organic compounds (VOSs). Terpene vapors may be unhealthy to breathe and for those with chemical sensitivity, terpenes are often intolerable .
The aroma from a cedar closet can often elicit symptoms in those with sensitivity to softwoods. Of the various softwoods available, fir, spruce, or hemlock are a little less odorless than pine or cedar if you can smell or notice the wood aroma such as a pine scent – it is off gassing. The smaller your tiny house or home, the more of an issue this becomes for the occupants.
We build non toxic and healthy homes and will not use SPF in any part of the structure, exterior or interior trims.
CAULK & ADHESIVES
Caulk and adhesive may seem like a small part of a building project, but they can make a big impact on air quality. Solvent-based adhesives have high levels of volatile organic compounds (VOCS), making them harmful to work and live with. Epoxy adhesives are noxious during application but relatively nontoxic when fully cured. White glue (polyvinyl acetate) and carpenter’s glue (yellow aliphatic resin) are safe when dry.
Healthy adhesives are solvent-free or water-based. Caulk with a VOC content of 30 grams per liter or less is acceptable.
CABINETS, DOORS, MOLDING, SHELVING, TRIM
These days conventional cabinets, doors, molding, shelving, and trim are often composite wood covered with veneer to make them look like wood. These products contain large amounts of formaldehyde. In a healthy home, cabinetry, doors, and built-ins are made of solid wood or formaldehyde-free wheat board (a rapidly renewable resource) and finished with a low-VOC paint or stain. Formaldehyde-free exterior-grade plywood is an acceptable material choice, or use alternative materials, such as metal with a baked-on finish, for cabinets.
SUBFLOORS, SHEATHING, UNDERLAYMENT
Subfloors, wall sheathing, countertop underlayments, and some types of wall coverings use plywood or other composite wood products containing urea-formaldehyde binders that can offgas for years. When using sheetgoods choose low-emission boards such as wheatboard, strawboard, isoboard, Fiber Tech™, Homastote™ (made from wheat, straw, sugarcane, or recycled paper bonded with nontoxic agents), or exterior-grade plywood. Seal it with a low-VOC vapor barrier sealant and finish with low-VOC paint.
Though plywood is not a healthy choice, exterior-grade is preferable over interior-grade. The phenol formaldehyde binders of exterior-grade are waterproof and more stable than the urea formaldehyde binders of interior-grade, which are only water resistant. It is best to seal exposed surfaces with a vapor-retardant sealer.
In a healthy house, countertop finish material is installed over formaldehyde-free underlayment and fastened and fastened mechanically, when possible, to avoid the issue of adhesives. Avoid high-pressure plastic laminates. They contain PVCs and are often attached using high-VOC adhesives. Though more expensive, materials like marble, granite, concrete, ceramic tile, and stone are healthy choices. Solid-surface synthetics don’t offgas, but they are manufactured from petroleum, so they are not “green.”
Butcher block makes an attractive kitchen countertop, does not require underlayment, and can be mechanically fastened to cabinets. The porous surface, however, can encourage mold and bacteria growth. Be sure seams aren’t glued with formaldehyde-based adhesives. Finish with odorless nontoxic oil, such as mineral oil.
Stainless steel and copper are excellent choices but present issues with creating electromagnetic fields.
New eco-products are available. Vetrazzo® (made of recycled glass from curbside recycling programs) is touted as a sustainable alternative to granite, quartz, and other quarried stone. IceStone® (composed of recycled glass and concrete) is another option. Both come in an array of colors, are strong like granite, yet not as porous as marble and heat-resistant like stone.
Though economical and convenient, gypsum-based drywall (also known as Sheetrock®) is not a healthy material for two reasons: (1) adhesives and joint compounds offgas irritating fumes (including formaldehyde), and (2) drywall is subject to moisture damage and mold. Chemically sensitive people often react to offgassing of inks used in the recycled newsprint comprising the paper facing. A less toxic solution is drywall primed with specialty paint or primer to seal off toxic fumes, and joined with no-tox joint and texture compound, such as Murco M-100 Ni-Po, made with inert fillers and without formaldehyde and preservatives.
A new type of paperless drywall by Georgia-Pacific (DensArmor Plus®) is a highly mold resistant gypsum panel, ideal for basements and bathrooms. The glass-mat surface front and back make it a healthy replacement for paper-faced greenboard.
The most natural wall finish (short of adobe) is additive-free plaster. Plaster has the added advantage of blocking VOC offgassing present in the gypsum and taped joints of modern construction. As an added bonus, colored plaster never needs painting. Traditional plaster and lath construction is many times more expensive than drywall-if you can find someone to do it. Fortunately, veneer plaster systems (often called skim plaster) are available that provide many of the same benefits of traditional plaster for a price similar to standard drywall. Veneer plaster is simply a layer or two of plaster installed over special drywall for a smooth, seamless, and impermeable finish.
Because it covers such a large surface, nontoxic floor coverings are essential in a healthy home. There are more choices than ever before, so it’s essential to do your homework.
No matter what type of flooring you choose, if it would ordinarily be finished on-site, consider a factory-finished product instead of one you finish yourself. The factory finish allows it to cure outside the home, thus lowering in-home emissions. IF you choose to finish it on-site, select a low- or no-VOC water-based adhesive.
Healthy flooring choices include ceramic tile, slate, terrazzo, brick, hardwood, pine, natural rubber, “true” linoleum, and colored concrete. Instead of wall-to-wall carpet, cover these floors with easy-to-clean natural fiber area rugs.
Avoid vinyl flooring. Vinyl chloride fumes are a known carcinogen. Vinyl also traps moisture which can promote delamination of subfloors and mold growth or rot, especially in hot, humid climates. In older houses, be careful removing vinyl flooring; they may be a source of asbestos.
Instead of vinyl, choose “true” linoleum (made from wood and cork “flour,” limestone dust, pine resin, and colorants mixed with linseed oil from flax seeds and baked onto jute backing). It’s durable, resilient, thermally insulating, quiet, and low maintenance with natural antibacterial properties. Available in sheets or tiles, it doesn’t show scratches or cuts and comes with a 30 to 40 year lifespan. One type, Marmoleum®, looks and feels like old-fashioned linoleum, is cushy underfoot, available in a variety of colors, and can be cut and inlaid to create one-of-a-kind patterns.
Similar to linoleum is natural rubber. It’s durable, resilient, and easy to clean. Newer types of rubber flooring come in either rolls or tiles and cost $3 to $5 per square foot installed. Be leery of manufactured rubber flooring, though. Some are made of recycled tires which can outgas for a long time.
If you choose a hardwood floor, pay attention to the type of wood. The environmental choice is Forest Stewardship Council-certified wood (FSC). Be sure the underlayment doesn’t contain formaldehyde. An installation that requires no glue (as in most traditional hardwood floors) is best, but if the floor must be glued use water-based glues. Finish the floor with a low- or no-VOC finish. Or, you may find a great deal on recycled wood in salvage yards and neighborhood teardowns, thus reducing the $3 to $8 per square foot cost of installing a conventional hardwood floor.
As a substitute for hardwood, check out renewable products such as cork and bamboo. Bamboo resists warping better than other types of wood floors and is surprisingly firm. Be careful, though. Most bamboo flooring is manufactured in China and may have adhesives and finishes that contain formaldehyde. Do your homework and select formaldehyde-free bamboo. Cork has natural give, thus cushioning the foot, is durable, sustainable, provides acoustic and thermal insulation, and has antimicrobial benefits. When using cork, make sure it it not encased in vinyl. The price of installed cork is at the upper end of the range for wood flooring, and bamboo will cost $1 to $2 more than cork per square foot.
Beware of laminated flooring. The backing may be composite wood. Some are bonded with PVCs, which are harmful throughout their life cycle. Look for laminated floors using natural materials and biodegradable resins.
When it comes to insulation, there’s a mind-boggling array of choices, so you need to be informed.
If anyone in the house is chemically sensitive, stay clear of batt insulation backed with asphaltic coatings. Batts are not the most effective insulation, anyway. Blown-in loose-fill insulation is the better option because it doesn’t settle as much as spray-in insulation does. IF you want batt-type insulation, try a new product made of recycled blue jeans. UltraTouch NaturalFiber Insulation® by Bonded Logic is safe to handle and install, contains no formaldehyde binders, and provides better acoustics than fiberglass.
Though fiberglass is the most popular insulation, home ecologists discourage blown-in fiberglass insulation unless it is formaldehyde-free (such as Climate Pro® or Attic Protector® by Johns Manville Corporation, and Insulsafe 4® from CertainTeed Corporation).
Cellulose insulation has high energy and acoustic performance, and isn’t harmful to the installer, but chemicals in the ink of shredded newsprint make cellulose bothersome to some chemically sensitive people. If using dry or damp sprayed cellulose:
Choose a product made of recycled cardboard; second best is newspaper.
Fire retardant should be boron, not ammonia-based.
Damp applied cellulose must be allowed to fully dry to under 25% moisture content.
In general, avoid polyurethane-based expanding foams for indoor air quality issues. Cementious expanding and plant-based expanding foams (such as Air Krete® and BioBase 501®) are healthy options, but must be installed by an experienced local installer per manufacturer’s instructions.
Similarly, avoid spray polyurethane foam (SPF), which can outgas if not sealed by drywall or plaster, and some chemically sensitive people may react to it. Rigid foam insulation, popular in the 1980s, outgases badly and should not be used on interior applications.
Other no-tox, high R-value solutions include cork and wool (check out wool batts by Good Shepard Wool Insulation).
PAINTS, SEALANTS, STAINS
More than 10,000 synthetic chemicals are used in conventional paints, sealers, and stains; many are toxic solvents, mildewcides, and fungicides. Such chemical-overburdening is unnecessary. You can now find low- and no-VOC paints, stains, thinners, and waxes made from naturally derived raw materials. Choose water-based materials with a low VOC content of 150 grams per liter or less. Ventilate well during and immediately after painting or sealing.
At Tiny Green Cabins we use a walnut oil beeswax mixture occasionally and Tung oil. We prefer the Tung oil for ease of application and ease of applying subsequent coats. if you really want a workout, the Walnut oil and beeswax mixture will bring that satisfaction. You can read more about these finishes here.
A WORD ABOUT CARPET
The healthy home avoids chemically treated carpets. Choose natural fiber carpets and rugs, instead, particularly those made of pure wool, cotton, hemp, jute, ramie, sisal, seagrass, or coir, with a natural backing such as felt or jute. The best are certified organic and undyed. Natural fiber modular carpet tiles (which can be installed wall to wall or as a rug) are decent options. If you damage on tile, you can pick it up to clean it or replace it. Just be certain the product hasn’t been chemically treated.
If you choose carpet, ask the retailer to unroll it in the warehouse and leave it unrolled for a couple of weeks. When in comes time for installation, tack it down instead of using glue. For carpet that needs glue, choose a low-VOC adhesive. After installation, keep windows open and a fan going for two or three days.