Bamboo Flooring

Historical Use and growth of industry:

The international roots of the bamboo flooring industry started in earnest in the mid 1990’s, though before then it was a small cottage industry in China, with a very production quantity.  Initial introduction into North America was done by several importers and brokering agents.  Though initially fringe, it coincided well with the advent of the green building industry that adopted the material due to its rapid growth and reasonable cost relative to the traditional wood flooring.  As the green building industry began to take hold, so did interest in bamboo flooring, this in turn created manufacturing interest overseas.  Starting around 2000, there was a manufacturing boom in China for the bamboo flooring, which for all intents and purposes is the hallmark location for bamboo flooring manufacturing (Vietnam also began, but with much less emphasis and investment).  The once impoverished region around Anji (Zhejiang Province; one of the poorest areas in China) realized that its vast store of bamboo forests was to be the boon for their economy, and bring riches to the poor.  This area, to this day, is known as the Sea of Bamboo, and really where the majority of all the commercially available bamboo comes from.

Different options/types:

There are 2 main types of bamboo flooring, strip flooring (aka: “traditional”) and strand flooring (aka: “strandwoven”).  Strip bamboo flooring is made by splitting a bamboo pole into small strips, and then gluing the strips together once they are planed.  These strips can be glued along their short side (ie: edge-to-edge), and it produces the “horizontal” (or flat sawn) cut.  When the strips are glued along their long side, this is called “vertical” (or rift sawn) cut.  Both orientations offer a clean and distinct look.  The strand flooring is made of shredded strands, as opposed to rectangular strips.  Instead of being glued together in an oriented pattern like the strip flooring, the strands are compressed generally in a lengthwise orientation without a definitive axis of joinery.

Horizontal Natural Bamboo

Vertical Natural Bamboo

Strandwoven Light Bamboo

Horizontal Carbonized Bamboo

Vertical Carbonized Bamboo

Strandwoven Dark Bamboo

There are several notable differences between strip and strand bamboo flooring, with the manufacturing methodology and resultant product and its’ attributes being the main differences.  Strip bamboo has a very consistent look since the pieces are glued in one of two repetitive ways (edge-to-edge or side-to-side).  The hardness of the strip flooring correlates directly with the hardness of the core bamboo material, with a differing hardness between both the horizontal and vertical products, and between each of these products over time (as the material is sanded; vertical has a more consistent hardness over time, while horizontal has a slightly greater hardness at the beginning, and then as sanding occurs, softer parts of the bamboo are shown).  Strand bamboo, due to the different manufacturing process used to make it, has different aesthetic and functional attributes.  The aesthetic is much more exotic in the sense that it is not as consistent as the strip bamboo.  From a functional, and mainly hardness standpoint, the strand bamboo is approximately twice as hard at strip bamboo, and this is mainly due to the compression, smaller fiber size, and greater amount of glue used in the compression.

Comparison to traditional products:

Bamboo has been “marketed” in a number of lights since it came onto the market, some straight forward and accurate, and others mired more in trying to prove superiority more than relaying fact.

NOTE: Before too much is shed on this, it is important that one understands that bamboo is a raw material, and it can be treated in different ways (different additives, different manufacturing methods, etc)., to produce completely different products.  The adage, “not all bamboo is equal” is a true in bamboo flooring, as “not all vehicles are the same” is true in a simplistic comparison of a Rolls Royce versus a mini-scooter (they are both a vehicle of providing transportation, but they have more differences than similarities).

Without getting into the minutia of all the manufacturing differences here, a simple and true statement is that strip bamboo flooring tends to scratch easier than similarly tested woods (in hardness testing).  It is one of the weird characteristics of bamboo that the stacked parallel cellular fibers are difficult to penetrate to the depth of the normal wood testing instrument, but it is relatively easy to scratch on the surface or to a superficial depth.  This is one of the main issues when comparing strip bamboo to other traditional wood flooring products – the comparison is not apples to apples, since one product is a grass and one is a wood; the cellular structure is just different, and it acts differently.  So, understanding this, it is probably best to characterize bamboo’s comparison to other materials in two ways: hardness (measured as a resistance to normal scratching, and then also resistance to deep gouging by a high point load) and then stability.  Strip bamboo probably has a resistance to scratching like pine (relatively soft), but a resistance to deep gouges more like oak or maple.  From a stability standpoint, strip bamboo would be on par with the most stable of wood species (mesquite being the most stable when acclimated), and this characteristic does not vary over time.

Insider Knowledge:

The differences between the various bamboo brands can be tremendous, and this has been one of the over-arching issues with bamboo’s overall acceptance – there is good bamboo flooring products, and then there are horrible ones.  And, for the horrible ones, you can be guaranteed that the person selling it would never tell you that.  The main differences that affect the products’ overall quality are: harvesting, glues and chemicals used, and ability to dry.

Harvesting affects the hardness of the bamboo raw material.  Being that bamboo grows to its’ full height in 3-4 months, and then internally matures over the coming years, it is easy to understand that if you use immature raw stock material, it will be softer than material left to reach its’ maximum density.  Though most manufacturers buy their bamboo stock on the commodity market (within unknown sources and ages), several control it from growth to harvest and can therefore ensure the bamboo is at its’ peak hardness.

Glues and chemicals used relate more to toxicity than durability, though very inferior glue can lead to product failure, toxicity aside.  Glues used in making bamboo are generally of one of two types: phenol and urea based.  Both are a formaldehyde derivative, though Urea is considered a toxic carcinogen and Phenol is considered relatively inert.  Where quality matters and low toxicity is important, phenolic resins trump, albeit more expensive to buy and use.

Drying is critical with regards to acclimating the flooring product.  Being that most of the bamboo comes from sub-tropical environs, it needs to be artificially dried (ideally in a kiln) to bring it to a suitable moisture content percent so once it is installed it does not shrink wildly (or change shape in other ways).  Drying equipment and the operational costs to run it costs money, and this too is a product differentiating component.

Potential for market confusion (green-washing):

Greenwashing is relative rampant within the bamboo flooring category, both because a lot of the attributes and characteristics mentioned above are foreign to many who sell the product, and they tend to take the approach that “all bamboo is equal”.  If they do not see the “spec” info that is asked of them, they may find another product that has done the testing, and then take that information as their own.  So, this could just be naive sales people, or it could be fraudulent marketing, depending if the salesperson is more interested in selling than educating – also a problem.

Possible Certifications (and what they mean):

Some bamboo flooring products are FSC-certified, with the merits being debated ad nosium.  Afte all, bamboo is rapidly renewable, and a very sustainable raw material, so is there really a value in having the material come from a third-party managed forest, when all of the bamboo plantations are managed regardless.  Some claim it just a marketing ploy to separate and differentiate, which others see it as a component to the understanding of that manufacturer to understand the value of sustainability and healthy forest management.  If a manufacturer has paid the fees to source FSC material, they likely understand the intrinsic value in using low-VOC glues.