Bamboo Flooring Hardness

Concern for the environment is growing as rapidly as a stalk of bamboo. And the popularity of bamboo flooring is growing just as fast.

Bamboo is proving to be a hardy and attractive alternative to hardwoods. It’s easy on the environment, as it can grow to maturity in five years, compared to 50-150 years for many hardwoods. It’s sturdy, with a hardness that rivals, and in many cases exceeds, the hardness of many hardwoods. It’s attractive — available in solid, woven and engineered versions, it offers a variety of colors and grains. And it’s cost-effective, often less expensive than hardwoods and easy to install.

Hardness in woods is measured by the Janka Scale. The hardness of bamboo flooring depends on the type and the way in which it is manufactured. Solid bamboo flooring is made out of milled splits of bamboo glue-pressed together. Woven bamboo flooring uses thousands of bamboo strands pressed together under high pressure. And engineered bamboo flooring is usually comprised of an outer layer bamboo layer over a pine and rubberwood backing.

Woven bamboo flooring is the hardest and rates 3000 on the Janka Scale, significantly harder than Brazilian Cherry (Jatoba), which is rated at 2350. Solid bamboo flooring rates at 1640, harder than white oak, rated at 1360. And engineered bamboo flooring rates from 1350-1600.

Janka Scale:

- Woven Bamboo 3000
- Brazilian Cherry (Jatoba) 2350
- Solid Bamboo (natural color) 1640
- White Oak 1360
- Engineered Bamboo 1350 to 1600
- Red Oak 1290
- Solid Bamboo (darker color) 1120
- Black Walnut 1010
- Teak 1000

The inherent hardness, combined with a tough finish (often acrylic), makes bamboo a durable choice for flooring. A number of manufacturers provide warranties for residential applications of as much as 27 years.

The surge in popularity of bamboo flooring has created a rush to market with a concomitant surge in manufacturing capacity. The quality of the finished product varies widely, depending on the manufacturing processes used. As with most products, many manufacturing variables determine the ultimate quality of bamboo flooring, including the following:

Stalks should be processed quickly after cutting. Otherwise they can develop a surface mold that is often visible in the finished product. Quality manufacturers process their cut stalks immediately, eliminating the possibility of mold.

Moisture content should be as low as possible. It can vary widely, from 7% to 14% and depends on the quality of the manufacturing process. Manufactures of high quality bamboo flooring achieve the lower end of range.

Denser is better. Wood filler and adhesives are used to fill and bind the bamboo material. Manufacturers that use higher compressions during the crushing process are able to use less wood filler to fill the voids between the larger strands of bamboo than those who use lower compressions.

High quality adhesives should be used. Low quality adhesives, especially those containing urea-formaldehyde adhesive, can emit harmful off-gases in the home.

Installation of bamboo flooring is straight-forward and similar to the installation of hard wood flooring. Both solid bamboo and woven bamboo flooring are available in tongue & groove configurations, and can be either glued or nailed to the sub-floor.

The growth in the use of bamboo for green flooring is not surprising. Bamboo is a solid choice: it’s attractive, durable, reasonably priced - and easy on the environment.

References:

- Leadership in Energy and Environmental Design for Homes (LEEDS)
http://www.greenhomeguide.org/green_home_programs/LEED_for_homes.html

- Janka Wood Hardness Scale
http://en.wikipedia.org/wiki/Janka_Wood_Hardness_Rating

- Environmental Bamboo Foundation
http://www.bamboocentral.org/