Navigating the flooring thicket: Find the greenest way to meet your needs
Your choice of flooring material will affect everyone in your home for decades, as well as the wider environment.
Floors usually account for more surface area than anything else in a house except the walls, so they have an outsized effect on indoor air quality. Adults, children and pets will walk on them, play on them, sit on them, wear them down and breathe anything they emit.
Since flooring may take up thousands of square feet, large quantities of raw materials, glues, finishes, adhesives and cleaners—with all their associated environmental impacts and energy requirements—are required to make, move, install and maintain it. But you can select flooring materials that will help you maximize the quality of your indoor environment while minimizing damage to the natural environment.
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Disadvantages of vinyl
Some flooring types are clearly at odds with these goals. Polyvinyl chloride (PVC) flooring is a prime example. Because it’s relatively inexpensive and easy to install, it’s one of the most popular flooring choices—14 billion pounds of it are produced each year in North America. But from a health and sustainability standpoint, it couldn’t be much worse, according to Marian Keeler, green building consultant and author of Fundamentals of Integrated Design for Sustainable Building (Wiley).
“Vinyl presents a health hazard across its entire lifecycle, from production to installation to use and disposal,” Keeler says, noting studies that show a correlation between the plasticizers found in vinyl and childhood asthma.
Vinyl is the poster child for many things you should avoid if you want to create a safe, green home:
- Vinyl manufacturing creates dioxin, vinyl chloride and ethylene dichloride, which can affect the environment in surrounding areas.
- Vinyl is a plastic based on nonrenewable petroleum, and the oil needed to make it usually travels thousands of miles to get to North America. This makes vinyl wasteful of raw materials and sharply raises its embodied energy cost.
- Once installed, vinyl may off-gas potentially harmful compounds (including lead, cadmium and phthalate plasticizers) for years.
- Once vinyl’s useful life ends, it will not decay in landfills, even though millions of pounds of vinyl tile are landfilled in the United States each year. Otherwise, vinyl must be burned at very high temperatures to avoid releasing poisonous dioxins. (The industry’s Vinyl Institute has claimed it is making progress in recycling, however.)
Key factors in choosing flooring
Most flooring choices are less clear-cut than vinyl—but vinyl’s problems are emblematic of the trade-offs buyers must consider when choosing flooring. For example:
- Stone is elegant and durable, but nonrenewable, and it requires large amounts of energy to quarry, finish, transport and install.
- Bamboo is rapidly renewable, but transporting it from Asia raises its embodied energy, and the glues and binders in some bamboo flooring contain potentially harmful aldehydes.
- Carpet is soft, warm and has excellent sound-absorbing properties, but it is relatively short-lived and attracts dirt, dust, pesticides and dander. In addition, nearly 5 billion pounds of it winds up in landfills each year.
Issues such as safety, renewability, embodied energy, durability, off-gassing and recyclability come up repeatedly when considering flooring, and there is no correct answer. The right option depends on your needs and tastes, and your desire for a house that’s safe for you and the environment.
A good place to start is with what builders call “programming,” the narrowing down of choices based on your needs. Consider:
- Desired flooring type (soft or hard)
- Room function
- Occupants (kids; people with allergies, asthma or chemical sensitivities)
- Cleaning and maintenance concerns
- Aesthetic requirements (color, pattern, texture)
- Acoustic requirements (baby’s nursery, older person’s room, entertainment room)
- Any other important requirements.
Once you’ve decided what you need from your flooring, consider the trade-offs involved in the materials that meet your needs. The following are the major factors in determining a flooring material’s environmental and health impacts:
Ideally, flooring materials originate with a renewable substance; for example, bamboo, wood and cork originate from plants. Although ceramic tile and stone are plentiful, they are not renewable, notes Andrew Mangan, an architect and builder in Los Angeles.
“The whole idea is to use and reuse and recycle, and use products that can be reharvested quickly,” he says. “Obviously stone can never be reharvested—over millions of years, maybe. I’d be happy if I didn’t use any natural stone, or any hardwood that wasn’t sustainable.”
How renewable materials like wood or bamboo are cultivated or harvested is crucial, so select sustainably harvested products. Look for wood and bamboo products certified by the Forest Stewardship Council (FSC).
Also consider products salvaged from existing structures (including wood, stone and tile) and recycled or partially recycled materials (such as rubber flooring made from used automobile tires). These have substantial mechanical energy costs, but require little additional input of virgin resources.
In general, the less a material must be modified during manufacture, the better. Stone, wood and bamboo require the least modification. Cork, ceramic tile, linoleum, rubber flooring and carpets and rugs require more energy (and potentially, chemical processing) to manufacture.
Some flooring materials (such as Asian bamboo or European linoleum) must be shipped great distances, increasing their embodied energy cost and total environmental impact. USGBC's LEED rating system recommends using materials that originate within 500 miles of your home to help keep embodied energy costs low.
“Ultimately, we want to reduce embodied energy in terms of transportation costs and in terms of emissions,” Keeler says, “so local is always better.” She notes, however, that embodied energy is a complex issue involving both weight and the transportation mode (sea, rail, truck, etc.).
Installation can require cutting, sanding, sealing and adhesive application to attach the flooring to the substrate in your house. It’s important to know how much these installation activities may affect indoor air quality. Water-based adhesives are generally better than solvent-based options. Green Seal's adhesives standard sets 150 grams of volatile organic compounds (VOCs) per liter of product as a safe maximum.
Use and maintenance
Once installed, most flooring materials will off-gas compounds—some of them inert, some potentially harmful—over long periods of time, according to Kirsten Ritchie, director of environmental claims certification at Scientific Certification Systems, an environmental testing firm in Emeryville, California.
One way to tell whether a flooring product is safe to have around for the long term is to look for the FloorScore seal, which Ritchie’s firm developed in conjunction with the Resilient Floor Covering Institute (RFCI). It certifies certain products as meeting California’s tough section 01350 requirements for indoor emissions.
Other well-regarded emissions standards may be considered when shopping. In Germany, the E1 standard mandates a maximum formaldehyde emission of 0.1 parts per million (ppm), while the U.S. Dept. of Labor’s Occupational Safety and Health Administration allows 0.75 ppm. Rather than parts-per-million, California’s Office of Environmental Health Hazard Assessment recommends 27 parts per billion for formaldehyde emissions; this is the same maximum as for FloorScore certification.
Maintenance and durability are important concerns for both the natural and the indoor environment. A less durable floor will have to be replaced more often, and a high-maintenance floor can expose you to more harmful chemicals. Stone, for example, requires frequent refinishing while other materials, such as linoleum, require little or none.
End of life
What happens when you’re done with your flooring? There are trade-offs here, as well. Synthetic carpet doesn’t decay, but increasing amounts of it are recycled into foam padding. Stone takes millions of years to decay, but it can be crushed tomorrow and reused as aggregate in stone tile or even highways. Linoleum, cork and wood are biodegradable or can be burned for energy.
Types of flooring materials
See Green Home Guide’s “Buyer’s Guide to Green Floor Materials” for a snapshot of eight types of eco-friendly flooring. Following is an in-depth look at each material’s pros and cons.
The world’s largest grass, bamboo grows quickly in a variety of soils and, depending on the species, can be harvested in a three- to five-year cycle. Bamboo flooring is generally made by slicing bamboo into strips, boiling it in water, laminating it into board and kiln-drying the resulting material.
Most bamboo flooring comes from the Asia Pacific region, particularly China and Vietnam, which means energy requirements and air emissions for transporting bamboo flooring to North America are significant.
Adhesives used in bamboo flooring sometimes contain a urea-formaldehyde resin, although products that contain minimal or no formaldehyde are available.
Installation is by nailing, stapling or gluing; tongue-and-groove flooring sections can minimize the need for fasteners or adhesives. Ask the installer to conduct as much sawing and sanding as possible outside the home, to minimize air quality impact.
Bamboo flooring is harder than many hardwoods, and will last for 30 to 50 years. Once removed, it will biodegrade in landfills or can be burned for energy. Doityourself.com offers a general description of bamboo floor installation and a short article on bamboo features and benefits.
Stone is nonrenewable. Sought-after stone types—granite, marble, sandstone, slate, limestone and others—may need to be transported long distances. However, stone’s durability amortizes these costs over a long period of time.
It requires only minimal processing, but as a heavy material, stone needs quarrying, cutting, polishing and handling, which requires a great deal of energy. Stone quarrying can also affect the surrounding landscape and water tables, and stone saws can throw irritating dust into the air.
Installation typically requires specialized knowledge and stone-cutting and -grinding tools. Ask the installer to conduct as much cutting and grinding as possible outside the home to minimize air quality impacts.
Stone has no emissions profile beyond potential radon emission. Query suppliers to ensure that radon is not a concern with a particular stone type. Select a low-VOC sealer to finish stone flooring, or select stone flooring that does not require sealing. Also, your stone flooring must periodically be resealed against stains—as often as every year for high-traffic areas. Sealer will evaporate eventually, even from unused areas. Beyond this, simply vacuuming a stone floor is enough to maintain its appearance.
Some stone types—particularly marble, sandstone, limestone and slate—are relatively soft,and can scratch and absorb stains easily. Granite is harder and more scratch- and stain-resistant. Stone flooring can last decades or even centuries, long enough that disposal is a minor issue. Stone can be disposed of safely in bulk, or crushed and reused as aggregate for other building materials, such as composite stone tile.
Read more about stone and tile in Green Home Guide’s article "Green stone and tile recommendations." Also, Stone World and Contemporary Stone and Tile Design magazines discuss and promote the use of stone in building and interior design.
Cork is highly renewable, although at a slower rate than bamboo. Even virgin cork is harvested sustainably in several Mediterranean countries. The bark of cork trees can be removed once every 7 to 10 years without harming the tree or its habitat, a process that has been used throughout recorded history. However, energy requirements to transport cork from the Mediterranean are significant.
Cork has a slight scent that most people consider pleasant. Some manufacturers claim their cork flooring is hypoallergenic, but in any case, all-natural cork flooring is preferred over cork-vinyl composites that have a PVC backing. In the past, urea formaldehyde was used to bind cork granules into flooring, but it was phased out in the 1980s. Today, urea melamine, phenol formaldehyde and natural proteins are used as binders instead, greatly reducing VOC problems.
Techniques for installing cork planks or tiles vary from nailing to gluing; take care to choose low-VOC adhesives. Tiles will need to be sealed, so look for a natural wax or low-VOC polyurethane sealer.
Cork flooring keeps its shape well and is naturally resistant to mold, moisture and rot. It’s as durable as hardwood flooring and is biodegradable and nontoxic. It can even be ground up for compost.
Ceramic and glass tile have been used as flooring materials for thousands of years. Some recycled-content glass tile is made from lightbulbs, ground glass and auto windshields. Although energy requirements for producing ceramic tile are high, it is durable and produced in many locations from abundant natural clays. Choose tile from a local source to reduce energy used in transporting this heavy material.
Ceramic tile set in cement may be the most acceptable floor in terms of indoor air quality. It’s also more durable than tile set using adhesives. Tiles come either glazed (sealed with a smooth finish and highly moisture- and stain-resistant) or unglazed (somewhat coarser and more porous). Tile glazes are inert, since they are baked onto the tiles at high temperatures, but as usual, adhesives should be chosen with care.
This type of flooring requires some specialized tools and knowledge to cut and install; however, it can be laid with simple Portland cement–based grout, which does not emit vapors and requires very little maintenance. Ask the installer to avoid cutting and grinding tiles inside your home as much as possible.
Ceramic tile will outlast vinyl flooring if properly installed, and it biodegrades after removal. Tiles can be reused or crushed and recycled as aggregate material for sidewalks and roads.
Check out the Green Home Guide listing of tile and stone providers near you.
Wood flooring has a warm feel architecturally, and recycled woods in particular add warmth to a space because of their years of weathering. Virgin hardwood flooring must be harvested from trees with long growth cycles: red and white oak, maple and occasionally, ash or birch. North American beech is depleted and should be avoided. Growth cycles for softwood flooring, such as pine, are somewhat shorter. Clear-cutting and overharvesting are concerns, so take care to purchase flooring that is FSC-certified or otherwise sustainably harvested.
“The obvious ones [to avoid] are hardwoods that are rare and endangered, which is what most people put in their homes,” Mangan says. “Brazil cherrywood is popular, and that’s not sustainable.”
That said, any wood may be sustainably raised and harvested. The U.K.-based Friends of the Earth rates woods on their endangered status in cases where no FSC alternative is available.
Increasingly, building suppliers carry salvaged wood, which avoids the energy cost of growing and harvesting new wood (though energy is required to disassemble the source building). Wood’s long replacement cycle also distributes its environmental impacts over decades.
Laminate flooring combines several layers of materials (typically a laminate, an “image layer,” a core and a backing) to create an aesthetically pleasing, highly durable surface. Note that while laminate flooring may contain sawdust, wood chips and other reused wood residues, it may also contain formaldehyde, a known toxin. Look for a FloorScore seal on laminate flooring or check its VOC emissions against one of the other emissions standards in the “Use and maintenance” section above.
Hardwood floors are excellent for indoor air quality, but take care in selecting a finish. It’s best to buy wood flooring prefinished at the factory, where off-gassing can be handled in a controlled environment.
Wood floors require sealing; try to choose adhesives and sealers that give off few or no VOCs. Wood itself off-gasses only minimally and does not harbor dust mites or mold. Properly finished floors retain only minimal dirt.
Linoleum is experiencing a big comeback as an alternative to vinyl tile. In addition to being more environmentally friendly, linoleum also has practical advantages over vinyl: patterns are dyed all the way through to the backing, ensuring even wear, in contrast to vinyl tiles, which have a pattern superimposed on them and show wear more dramatically.
Linoleum is a mixture of linseed oil (from flax plants), pine resin, wood flour, cork flour, limestone and pigments, which form into granules and are pressed together onto a jute backing. All natural linoleum is manufactured in Europe, adding to energy costs for transporting it to North America. (Make sure you look for “natural linoleum,” as “linoleum” is sometimes used to refer generically to vinyl flooring.)
In use since the mid-1800s, linoleum’s chemistry is well understood, although some have raised concerns about aldehydes off-gassing from linoleum’s constituent linseed oil. Linoleum’s faint scent may not be to everyone’s liking. However, linseed oil is a natural antimicrobial agent, making linoleum a good choice for kitchens.
Linoleum is not recommended for areas where moisture may seep through the underfloor, such as concrete basements; however, its edges can be heat-welded, eliminating seams for greater moisture resistance. Dry cleaning is considered more effective than wet cleaning, so linoleum flooring reduces water waste.
To find low-emitting linoleum and other resilient flooring, see Scientific Certification Systems’ list of FloorScore-certified products.
Rubber is generally used for play areas, outdoors and in other places where non-slip surfaces are needed, such as kitchens. Virgin rubber is manufactured from latex, the sap of rubber trees, which typically grow in tropical areas. Asia provides most of the world’s natural rubber; rubber can also be produced synthetically.
Several varieties of rubber flooring are made from recycled materials, typically rubber tires, meaning that there are abundant raw materials in North America. Conversion to rubber flooring requires energy but transport costs are generally lower than for imports. Recycled rubber flooring is generally less expensive and more durable than virgin flooring.
Rubber’s properties and effects are well understood after more than a century of industrial, commercial and residential use. It is chemically stable, although it does off-gas slightly, giving it a distinctive smell, but emission of toxics is low. Because of its natural tackiness and form-fitting qualities, it can be installed without adhesives, further lessening off-gassing compared with other materials. It is easy to clean, provides good support and is highly durable.
Rubber flooring usually is flammable and some people are allergic to it. Although hypoallergenic products are available, you may be better off using it only outdoors if you have sensitivities.
For specific product recommendations, consult the GreenSpec directory of environmentally preferable building products and Scientific Certification Systems’ list of low-emitting FloorScore certified products.
Start examining a carpet by looking for the Carpet and Rug Institute seal of approval, called Green Label Plus. For this certification, the CRI has adopted California’s rigorous 01350 standard, which tests for emissions of individual VOCs rather than just the overall level of VOCs.
Synthetic carpeting is commonly criticized for its petroleum-based fibers and the off-gassing of VOCs in the home. Binders still used to make synthetic carpets and padding may outgas for years after installation, with varying levels of emissions and toxicity. Recycled carpeting is made primarily from post-consumer plastic soft-drink containers, while recycled carpet padding can be made from old carpet padding and reclaimed carpet fibers. Amazingly, about 30 percent of all foam cushion used for carpet padding in the United States comes from imported waste fibers.
Natural carpets and rugs can be made from wool, cotton or even grasses with minimal processing and treatment.
Wall-to-wall carpets of all kinds require either an adhesive or the use of stretching and carpet tacks. Because of off-gassing concerns, ask the installer to unroll and air out the carpet in a well-ventilated area before installation, and to use only low-emitting adhesives. Ventilate the installation area as well as possible for 48 to 72 hours afterward.
Once installed, carpet has excellent sound- and thermal-insulating properties. The problem, Mangan says, is that it can’t be kept truly clean.
“Carpet not only is typically made from petroleum products and doesn’t break down ever, but it never gets clean; it just collects dirt and dust and stuff,” he says. “It’s always going to contain whatever’s fallen into it.”
While carpet is the softest flooring material considered here, it also requires relatively frequent replacement (about every 11 years). Just 4 percent of carpet is recycled, a figure the CRI says will increase to 20 to 25 percent by 2012.
Visit the Green Label Plus website for a list of carpets that have been tested and certified as low-emitting products.