floor covering and design...with a fuzzy side

Wednesday, April 30, 2014

Bamboo flooring: What everybody ought to know about this green, sustainable product

Did you know bamboo is actually a grass?  There are over 1000 species of bamboo.  Most bamboo flooring is made from the Phyllostachys Edulis species commonly known as 'Moso' bamboo.  It can grow up to 75 feet high and over 7' in diameter.

Typically, bamboo is harvested by hand, loaded on trucks and taken to a nearby processing plant.

The bamboo poles are broken down into 2m sections called fingers or fillets or even strips.

 (We are going to go with strips because I keep craving steak when I write fillet and fingers sounds just plain weird.)

During the milling, (breaking down the bamboo poles into the smaller sections...strips) the waste material (called strands) is collected to produce a very different type of bamboo flooring called strand woven bamboo. More on that later.

The strips can be either steamed under high pressure to carbonize the water and sugar  to give it dark coffee coloring then dried in low heat kilns to remove excess water or dried without the steam for a natural color.

The strips are then boiled to make it less desirable to insects (like termites) as well as making it less susceptible to the expansion and contraction that hardwood flooring experiences in humid climates.

 They are then dried in a kiln.

At this point, the dried strips are usually shipped to a processing building.  Most strand woven bamboo is manufactured in the same building where the strands are collected from the bamboo milling.
Once they reach the manufacturing plant, the strips are stored and allowed to acclimate before the process continues.

The direction of the desired grain (vertical grain or horizontal grain flooring) determines how the fingers are now glued together.   One on top of another (usually 15 strips high) for horizontal grain or side-by-side for vertical grain. Once glued, they are pressed under very high pressure to achieve the durability bamboo floors are famous for.

Solid vs engineered bamboo flooring

Solid bamboo flooring is comprised of only bamboo strips glued and pressed together.  It can only be glued or nailed.
Engineered bamboo flooring consists of bamboo strips on the topmost layer while underneath is layered with other types of wood. Can be nailed, glued or floated.

Back to the strand woven bamboo.  The strands (gathered from the waste when cutting the bamboo poles down to strips) are collected.  At this point the strands are either carbonized or left natural.  To carbonize the raw bamboo fibers are steamed under high pressure to carbonize the water and sugar  to give it dark coffee coloring. Both natural and carbonized strands are then ground up, soaked in a water based eco-friendly glue, put in a mold and put under extreme heat and pressure to create a beam.

 The beams are removed from the mold and cured for up to six weeks.  These beams are three times denser than teak.  

The beams are then cross-cut into planks.

The planks are stored to acclimate for up to three weeks.

Then the planks are finished.  Numerous coats of filler, sealant, anti UV and finish are applied.  All reputable bamboo flooring manufacturers use eco friendly water-based solvent-free products that do not contain formaldehyde in this process.

Strand woven bamboo flooring typically comes in only three colors; natural, carbonized and tiger strand (a combination of natural and carbonized).



Tiger Strand

Strand woven is twice as hard as regular (horizontal or vertical grain) bamboo.

 I'll be the first to tell you how hard a solid bamboo floor really is.  I purchased my floor from Bob Wagner's via Derr flooring and when the installer was putting it in, the staples from his staple gun were bending and required extra precision to get them to sink in correctly.
My dining room floor.

Carbonized strand woven bamboo in my dining room.

Why is bamboo considered a green product?

Because bamboo is a grass, there is no need to re-plant after harvesting.  It is cut at the base (by hand) then allowed to re-grow.  Because the plant isn't killed during the harvesting process, erosion does not occur.  Some bamboo can grow over a meter (3.28 feet) in 24 hours!  The majority of manufacturing plants are located not far from where the bamboo is harvested making the field-to-factory carbon footprint very small.

Hard wood takes 30-50 years to mature, while bamboo reaches maturity in 3-5 years.
The same square footage of bamboo produces more oxygen than many tree varieties.
Bamboo can grow and prosper in several different climates across the world.
Due to the durability of bamboo plants, no pesticides or chemicals are needed to encourage the maturation process, and they require much less water than trees.

The bamboo waste is used to make strand bamboo making it a zero waste product.

Some awesome videos:

Time lapse of bamboo growth over 24 hours:

How bamboo flooring is made:

A second video about the manufacturing process:

An explanation of what strand woven bamboo flooring is:


Click on photos for a direct link to photo credits.