Parts I and Part II of the Natural Cork Story explained the process of growing cork as a crop, the harvest, and turning cork into wine bottle stoppers. Part III gets a bit more complicated as we to follow the process of turning cork into flooring and underlayment.
The reason things get a bit trickier is due to the number of ways to produce cork flooring. The production of tongue & groove cork flooring, like any hardwood floor or laminate, includes many steps which differs between manufacturer, and even within a manufacturer between products.
Cork can replace traditional materials in three different parts of a manufactured flooring product:
The underlayment is what is layered down under the entire floor. If you've ever installed laminate or the such, you probably used a white or blue foam underlayment comprised of petrochemicals. Don't feel bad, I've done the same. There actually exists cork underlayment that is made from cork, serves the same purpose to cushion the floor, reduce sound, moisture, vibration and in the case of cork, also helps serve as a slight insulator.
Cork underlayment is made first by compressing lots of ground up cork into blocks.
These blocks are then glued together and cut into big spools. The spools are then put onto this machine which slides a thin layer of the cork into sheets, which are wound into reals of underlayment.
Making Cork Core:
The core of manufacturered flooring can also be comprised of cork with the same benefits of cork underlayment: insulation against temperature, sound, moisture, vibration and added cushion. Cork core can comprise a wood laminate flooring, a cork laminate flooring, or even a leather laminate flooring.
Cork core is typically made by taking ground up cork and spreading it across a moving conveyor belts. A hydrolic press that is also heated applies pressure and heat to flatten the cork into large sheets. In this case, no adhesive is used and the heat from the press activates natural binding agents within the cork to hold it together.
These sheets are then cut and can be used for flooring core.
Cork veneer or cork laminate is the top surface of the flooring product. Cork comes in so many different looks, shades and patterns that it's possible you've seen cork floor and not even known it. Chances are, you've also walked on a floor that had a cork core. So how does the veneer or laminate get made?
The mainway is for cork pieces to be combined into blocks, similar to those seen above and held together by adhesive, and sliced ever so thinly. They can be died different colors, mixed with different grain patterns, to create individual looks ranging from plain cork to exotic zebra stripes. Here are some pieces of laminate ready for application to a cork core:
Putting it All Together in a Finished Product
This is also where the process becomes a bit less pure than what we've experienced so far in the cork story. The process for making any laminate or hardwood panel flooring includes adhesives and finishes which are almost always not-so-friendly chemicals. What's good to know however is that cork flooring companies, in order to maintain their green image, are investing heavily in research towards greener adhesives and binders so that they can continue to produce a product that is better for the environment.
Also, this process is similar for all manufactured flooring, including bamboo. While there are a few processes to putting it all together, the basic idea is as follows:
The top layer laminate is placed over a piece of core coated with adhesive. Hydrolics are applied to help the pieces adhere. Pieces are cut, and then a final finish is applied to protect the cork laminate:
These lights help to speed the drying process:
Freshly cut boards ready to be packaged:
A recycled leather laminate placed over a cork core: