Although bamboo flooring’s looks, performance, and “feel” underfoot are almost identical to wood, bamboo is actually a fibrous, fast-growing, extremely strong type of perennial grass. Depending on the species and manufacturing process used, bamboo typically ranges from 25% to more than 200% harder than red oak. One brand of bamboo flooring is rated at over 5000 on the Janka hardness scale—making it more than three times more wear-resistant than hard maple flooring. Bamboo is so strong, according to one industry source, that its tensile strength (up to 28,000 pounds per square foot) exceeds that of steel (23,000 pounds per square foot). In Asia, where bamboo has been used for flooring, furniture, and building material for thousands of years, this tough, versatile, natural material is routinely employed as structural columns, high-rise scaffolding, and even concrete rebar in residential and commercial construction.
The Resource
Bamboo flourishes in the wild, primarily in tropical areas, and is also cultivated worldwide. China, Indonesia, Korea, the Philippines, and Vietnam are the main sources of bamboo used to make flooring and other products. China is the largest producer of bamboo products in the world—there are reportedly more than 1.6 million square miles of bamboo growing in China alone, with most of these native forests owned and managed by the Chinese government.
In addition to its commercial benefits, bamboo has unique environmental attributes. Unlike most hardwood trees, which take decades to mature and then die when harvested, bamboo is a rapidly renewable resource. One bamboo species has been “clocked” at almost 4 feet of growth in 24 hours—and reaches commercial maturity in just five to six years. And because only the culms, or individual stems, are harvested without harm to the roots of the plant, new bamboo culms quickly regenerate in a perpetual cycle. Bamboo also grows in dense clumps, which enables it to produce more usable material per acre than almost any other commercial “wood” source.
Experts say fast-growth plants like bamboo also absorb more carbon dioxide than other plant species, which translates into increased carbon sequestration—another environmental benefit. This captured carbon is transferred to the soil through the plant’s roots, and, if the roots are undisturbed, the carbon remains there instead of evaporating into the atmosphere to contribute to global warming. According to an article on bamboo cultivation in one publication, the World Wildlife Fund reportedly estimates that “an acre of bamboo can store 6.88 metric tons of carbon per year, about 70% more than an acre of hardwoods.”
Bamboo flooring production is not without its drawbacks, environmental and otherwise. The manufacturing process requires heating, adhesives, and finishing materials, in addition to transportation fuel and costs to ship the material from faraway sources (mainly in Asia) to users in the United States and other parts of the world—all of which contribute to bamboo’s overall carbon footprint.
“No bamboo flooring is made in the United States today,” says Anita Howard, a spokesperson for the National Wood Flooring Alliance (NWFA), which includes bamboo producers and distributors among its members. “Unfortunately, a lot of its green attributes are offset by the fact that it’s all imported.”
When bamboo flooring was widely introduced here in the 1990s, critics also condemned the natural habitat destruction that accompanied its early success and the poor manufacturing quality control that resulted in numerous product failures. Development of effective formaldehyde-free adhesives and low-VOC finishes over the past two decades has helped to restore bamboo products’ green performance and image, along with improved forest stewardship efforts that contribute to today’s high-quality flooring products.
Many bamboo flooring manufacturers now emphasize the environmental compliance of their products. Some producers, like Smith & Fong, maker of Plyboo flooring and one of the first companies to import bamboo flooring to the United States, have even developed their own proprietary low-VOC adhesives and finishes, and buy raw materials only from certified sustainable sources.
Bamboo flooring consumers should look for indicators such as the Forest Stewardship Council (FSC) and SCS FloorScore certifications, LEED qualification, and adherence to international standards such as ANSI ISO 14040/44 for environmental management and life-cycle assessment. One of the principal resources for bamboo flooring manufacturers worldwide, Moso International, notes that its 100% bamboo products have a “CO2 neutral” carbon footprint, based on a full life-cycle assessment following ISO standards.
Another complaint voiced about bamboo flooring is that, until recently, it was available only in limited colors. These ranged from bamboo’s natural pale yellow to darker gradients created by steam-heating, or “carbonizing,” the raw bamboo strips and fibers to caramelize the natural plant sugars—a process familiar to most cooks. As a result, many brown-hued bamboo flooring products are identified as “caramel” in color.
But claims that bamboo can’t be effectively stained or dyed are untrue, says Dan Smith of Smith & Fong. Consumers prefer wood flooring of all types to be natural in color, he notes, adding that many producers now offer a more extensive palette of colors, including special-order shades beyond “natural.” New coloring techniques, along with more durable surface treatments that help to retain surface colors, also allow manufacturers to offer a wider variety of bamboo flooring options.
Making the Spec
To make bamboo flooring, the plant’s cylindrical culms first must be cut into narrow strips or crushed to separate its fibrous material. The strips are arranged either horizontally or vertically and glued together under pressure to form laminated “plywood” planks that are then milled into flooring boards. This type of flooring is distinguished by the bamboo joints or “knuckles” visible in the flat-grain or edge-grain surfaces (also referred to as horizontal cane and vertical cane styles).
Alternatively, the separated pulp fibers are reconstituted with adhesives into strand woven sheet material and then milled into boards, which result in a more uniform wood-like grain. Strand woven flooring is generally stronger and more durable than other types of bamboo flooring, according to some producers, and is a more “eco-friendly” product than bamboo strip flooring because it requires less glue.
Engineered bamboo flooring, a relatively recent innovation, is also available. As with hardwood and laminate engineered flooring, a bamboo surface veneer is typically bonded to a substrate of wood or composite core material such as plywood or fiberboard.
All of the above types of bamboo flooring are sold in standard flooring formats, including unfinished or prefinished tongue-and-groove boards and parquet styles for nail-down, glue-down, or snap-lock applications. Some flooring brands are compatible with radiant floor heating (buyers must check product specifications). In general, bamboo is more dimensionally stable than many hardwoods, but like other woods it naturally expands and contracts, and it is susceptible to water and generally not recommended in wet areas like kitchens, baths, or over moisture-prone concrete surfaces.
The amount of urea-formaldehyde and other noxious chemicals used in adhesives and finishes, along with the VOCs they emit, varies widely among producers. Some bamboo products can be special-ordered with formaldehyde-free compounds, and many manufacturers today post VOC content specifications for their products or advertise their compliance with today’s rigorous environmental standards.
Buyers should be aware that although there are long-established industry standards regulating hardwood flooring quality and performance, no U.S. or international grade standards exist for bamboo flooring. The NWFA is working with the federal government to create these standards, says Howard, but the process is slow and complex, and “not far along.”
Until such standards become available, buyers have other options when it comes to ascertaining the quality, dependability, and environmental pedigree of bamboo flooring. Manufacturer and dealer warranties are available, and many dealers offer product information verified by organizations such as the Construction Specification Institute (CSI) and the FSC. At least one producer, Teragren, advertises its flooring products as FSC-Pure, a designation indicating that the bamboo is harvested in FSC-certified forests, manufactured with 100% FSC-certified materials, and sold through an FSC-certified “chain of custody” distribution channel.
Another quality identifier to look for is SCS FloorScore certification. Developed by the Resilient Floor Covering Institute and based on Scientific Certification Systems standards, FloorScore “rigorously tests flooring and adhesives for compliance with indoor air quality emissions requirements, and fulfills the compliance path to LEED credits for low-emitting materials and adhesives” in flooring systems.
Not all bamboo flooring qualifies for LEED or National Green Building Standard credits. However, products that have proper documentation and certification can qualify in renewable resource, low-emitting materials, and FSC-certified wood categories.
Michael Morris, a former carpenter and builder, reports on construction topics as an EcoHome contributing editor.
