Strand woven bamboo flooring was introduced into the flooring market around 2002-2003. In this format, the 1/4″ by 5/8″ sawn strips of bamboo that were cut from the bamboo stalk were now partially shredded to open up and expose the stringy bamboo fiber. Phenolic resins were then added and the shredded bamboo was pressed under tremendous pressure. The result was a “densified bamboo/resin composite” product that effectively tripled bamboo’s hardness. Like traditional bamboo, strand woven bamboo was offered with clear topcoats in the natural straw color, the carbonized caramel color, or a mix of both in a “tiger” color. In addition, the surface could be stained to the color of your choice prior to topcoating.
This new bamboo flooring category took quite a while to perfect in manufacturing, with early generations being prone to cupping, fiber raising, and checking post-installation. Additionally, it took quite some time for installers and mastic manufacturers to catch up to the proper methodologies to use when installing this product. Since strand woven bamboo, due to its resin content, does not “breathe” in the same manner as wood flooring it required a learning curve to install properly in various site conditions.
Bamboo flooring manufacturers have continued to search for ways to improve their product and have come up with a number of recent innovations. One of these involves dying the shredded bamboo fibers and adding tints to the phenolic resins before pressing them together. As a result the color is no longer just a stain on the top of the flooring, it is “fused” into the floor itself. Another innovation has been to expand the materials that can be used to create strand woven flooring. In addition to bamboo some of the natural fibers that can be used are recycled wood and coconut. Both of these are grown for other industries and now we can take the remains and turn them into beautiful eco-friendly flooring!
Bamboo was initially introduced to the flooring market in the early 1990s and since then it has continued to evolve into different flooring formats. As a result bamboo’s use and demand is on the rise, particularly among eco-conscious consumers.
What is Traditional Bamboo Flooring?
Traditional bamboo, the first iteration of bamboo flooring, was created by cutting round bamboo stalks into endless little strips approximately 1/4″ thick by 5/8″ wide. These strips were then laminated together into one of two formats. The vertical grain format, with numerous 1/4″ wide strips glued together yielding flooring that was 5/8″ thick, had a very linear look. The horizontal grain format was created by edge-gluing 1/4″ by 5/8″ strips together and then gluing 3 layers of these sheets face to face. The horizontal grain bamboo flooring, unlike the vertical grain bamboo, reveals the cross-width “knuckles” that are unique to bamboo. Both formats came in both the natural straw color and a caramel color produced by steaming the bamboo and either could be stained to the color of your choice.
This first-generation of bamboo flooring was launched with great fanfare into the U.S. market and was promptly marketed as harder than oak. Unfortunately much of it was in fact softer than oak and closer in density to walnut, and therefore was easier to dent when walking on it in high-heeled shoes. It was not long before manufacturers began looking for ways to improve bamboo flooring and in the early 2000s strand woven bamboo was introduced to the flooring market.
First there was traditional bamboo flooring, which became available in the early 1990s, then there was strand woven bamboo, introduced in the early 2000s. Now the latest big innovation in bamboo flooring is unfurled bamboo. Introduced to the flooring market around 2011-2012 this format creates a single sheet, approximately 6″ to 8″ wide by 1/4″ thick, from one bamboo stalk. A single slit is cut up the length of a bamboo stalk and then the stalk is carefully “unfurled” and flattened, forming a sheet whose width is equal to the circumference of the round stalk and whose thickness equals the thickness of the stalk. Now wide bamboo sheets can be made that have the knuckle running across the full width. This sheet can be used as is as a wear layer or three sheets may be laminated together in thickness prior to turning it into flooring.
Because of the way a single bamboo stalk is unfurled to create the sheet it is possible to leave the natural skin of the bamboo stalk intact. This means that there is no need for adding a man-made finish on top of the bamboo. However, if a tint or topcoat is desired, the natural skin can be partially removed and a traditional UV finish applied. Unique to unfurled bamboo being finished with UV finishes is the one-piece face with the knuckles running fully across the face. Bamboo’s unique cellular and fiber structure, whereby the outer skin is by far the hardest and most impact resistant part of the bamboo stalk, means that unfurled bamboo is extremely hard. Initial ball drop impact tests on the natural skinned, unfurled bamboo (which better replicate walking in high heels on the flooring than a lab Janka hardness test) amazingly show less denting than even on the densified stand woven format. And this we believe is the result of both the hardness of the natural bamboo skin coupled with the bamboo stringy fibers, which are largely concentrated in the bamboo stalk’s wall just under the skin, acting much like steel rebar used for tensioning and reinforcing concrete for strength. Or simply think of skin and underlying fibers in unfurled bamboo’s outer surface as a trampoline, whereby high-heel impact/ball -drop impact springs back as a result of the skin/fiber tension, producing little to no denting.
Given unfurled bamboo’s newness, it will be interesting to see how it performs in the market and whether it can match the excitement that strand woven bamboo generated when it was first introduced over a decade ago.