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History

Bamboo is an amazing natural resource that has been cultivated in China for over 4,000 years. It is a food source and food preservative, an ancient medicine, a paper, a musical instrument, a soil stabilizer, and a building material.

Characteristics

Bamboo is perhaps the fastest growing wood-type plant on earth with more than 1,000 species found worldwide. Some species of this giant grass can grow 2 to 3 feet per day, and they generally mature in 3 to 5 years. Bamboo regenerates by runners that grow into new canes, can grow in poor soils with little or no need for fertilization or pesticides, and requires less water and energy than coniferous or hardwood trees. When bamboo is harvested, it does not damage the grove or topsoil. Bamboo is sustainable, renewable, and produces about 25 times the yield of hardwoods.

The main sources of bamboo used in flooring and other products are the forests of China, Indonesia, Vietnam, Philippines, and Korea. For those concerned about the endangered panda, it is noted that the Giant Panda does not eat the species of bamboo that is used in these products. Additionally, panda habitat is at a much higher elevation and within different provinces than where most bamboo forests are located.

Hardness/Durability

Bamboo is a desirable building material and viable replacement for wood due to its durability, hardness, and stability. When compared to red oak, the most commonly installed type of wood flooring, it is about 25% harder and equally strong. Bamboo is naturally resistant to moisture and expands/contracts up to 50% less than hardwoods.

Manufacturing/Construction Types

Harvested bamboo poles are split length-wise and then undergo a boiling and shaping process. These splits are then kiln-dried, color-grouped, and laminated together in many layers. The planks are then milled to produce a variety of flooring styles.

Bamboo flooring planks come in solid and engineered forms. Solid flooring planks are constructed solely of bamboo and have their grain oriented in one direction throughout the body of the plank. Engineered flooring means that the layers of the planks are "cross-laminated." This type of flooring has bamboo on the surface layer, however, its core and backing layers are wood, often some variety of pine. "Cross-laminating" alternates the directional run of these layers, that is, if the grain of the top layer runs north-south, the grain of the core layer will run east-west, and the grain of the backing layer will once again run north-south. Engineered floors are designed in this manner for maximum dimensional stability.

Both types of flooring require glues to bind the pieces and strips together. While high quality bamboo floors may contain little to no formaldehyde in their adhesives, many lower quality products are flooding the market that have significantly higher levels of formaldehyde emissions.

Solid floors are less expensive to produce than engineered flooring, and therefore, cost less. Also, the fact that they are 100% bamboo makes them more environmentally appealing. On the other hand, manufacturers claim that engineered floors provide for extra stability and that they can better accommodate expansion due to temperature/humidity changes by use of expansion gaps in the core layer. Regardless of your choice, ensure a plank thickness of at least 5/8" for a more stable and durable floor.

Flooring Styles

The look of the bamboo floor is dependent on how the individual slats are constructed. Vertical and horizontal-grain orientations are the two most commonly available types. Vertical-grain orientation positions the thinner edge of the bamboo splits upwards. In this style, the bamboo joints, or nodes, are hard to discern which results in more consistent coloration and evenness of grain. Planks designed with the horizontal-grain orientation position the wider edge of the splits upwards. The bamboo nodes are more evident, and you will generally find about four node strands per plank.

Another style of bamboo flooring is known as strand, or woven. To manufacture these planks, the bamboo is shredded, mixed in glue, and compressed to create a very dense plank with a grain that is more similar to traditional hardwood flooring. The strand-style planks are about two times harder than standard bamboo planks. However, due to the quantity of glue required for this process, some manufacturers may use more inexpensive glues that contain formaldehyde; therefore it is important to inquire about the glue used in this, and any, type of bamboo flooring that you are considering.

Colors and Finishing

At a very basic level, bamboo flooring comes in two colors: natural blond and light caramel. The caramel coloring is achieved via a process called carbonization that uses heat to darken the bamboo without the need for dyes. There are some premium flooring lines that offer stained bamboo in various colors like cherrywood.

Bamboo flooring can be purchased either pre-finished or unfinished. The pre-finished planks are often finished with non-toxic aluminum-oxide which is a mineral resin. The layers of the aluminum-oxide are cured using UV rays and create a very durable, traffic-resistant finish. If the manufacturer uses something other than aluminum-oxide, you may want to find out if the finish contains VOC's, volatile organic compounds, which are potentially harmful gases. For healthier indoor air quality in your home, choose flooring that is finished with no- or low-VOC products.

Installation

Bamboo floors can be nailed, glued, or floated depending on the type you choose and your particular housing needs. Solid bamboo flooring must be nailed or glued to the subfloor; however, engineered flooring can be "floated." This means that the planks are glued together at only the edges rather than to the subfloor. Floating floors can be installed over radiant heating systems.

Pros and Cons

As a flooring product, bamboo's advantages are:

• Renewable, eco-friendly resource
• Durable, hard, and stable
• Sound alternative to hardwoods
• Increasingly affordable ($4 to $8 per square foot)
• Can be installed in most areas of the home or commercially
• Creates a beautiful, unique floor

However, because of its rapid renewability, some manufacturers are harvesting bamboo before it is mature enough to produce good quality, hard flooring planks (4 years of growth is recommended). Flooring that is made from these immature poles is soft and may easily warp, dent, and delaminate. Other problems with low quality production include the use of substandard glues that contain higher levels of formaldehyde, poor milling and pressing practices, and inferior finishes that contain higher levels of VOC's.

When choosing your flooring, review the manufacturer's warranties. Quality bamboo manufacturers will likely warranty their flooring for at least 10 years structurally and 25 years on pre-finishing. Additionally, ask to see their product specifications or Materials Safety Data Sheets to ensure that the finishing material is non-toxic and to review the product's glue emissions. If the glues used are not formaldehyde-free, verify that the emission rate meets or exceeds the strict European E1 requirements of no more than 0.1 ppm.

Do Your Homework

• Determine your flooring needs
• What rooms will you install it in?
• What type of subfloor exists in these areas?
• What is the approximate square footage of these areas? (add 15% for overage)
• How many years do you need the flooring to last?
• Gather color samples from the rooms to help with your floor color selection.
• Determine your budget, inquire about sales.
• Seek out higher quality manufacturers (cheaper prices usually mean lower quality)
• Review manufacturer's product specs, check warranties
• Surf, surf, surf -- information on bamboo, manufacturing, and retailers on the web is exhaustive!

If you would like a hands-on look at the various types and styles of bamboo flooring, please stop in at Town Hall and check out some samples. Please call me to ensure that I am available to assist you; I can be reached at (650) 851-1700 ex. 11.

If you have a green building topic you would like explored further in an article on this web page, please feel free to provide me with your suggestions at cborck@portolavalley.net or via telephone.

Please review other editions of "Carol's Green Feature."

• You Can Go Tankless!
• Window Shopping
• Walking on [Hot] Water With Radiant Hydronic Heating
• Insulating Green with Blue Jeans
• Uncommon Counters
• Checking Into Decking
• Weaving Nature Into Carpets