As everyone knows, cork is obtained from the bark of a tree called cork oak. The cork oak only thrives in seven Mediterranean countries: Portugal, Spain, France, Italy, Morocco, Algeria and Tunisia, which total more than two million hectares. Spain, behind Portugal, ranks second in the world ranking of cork production. And the regions that monopolize the landscape of cork oaks are: Andalusia, Extremadura and Catalonia.
The main use of the cork extracted is for the manufacture of stoppers, leaving for the construction sector the surplus from which, once crushed, other products will be obtained: coatings, insulators and agglomerates.
The way of marketing cork for the construction sector is in panels, tiles and rolls. However, we can also find it in blocks, granular, ground, etc.
Regarding its use, we must emphasize that the cork for floors is treated with sealing products and varnishes that increase its resistance and impermeability . In addition, and for aesthetic reasons, dyes are used that give us a great variety of shades. And, therefore, it is essential to ensure that these varnishes, sealants and dyes, are environmentally friendly and environmentally friendly. Its placement is very simple, since you just have to glue it with adhesive to the existing support.
The cork for walls and ceilings can be placed as a decorative coating on tiles, or as an insulating material , on agglomerated, granulated or expanded black cork sheets with a thickness greater than usual.
Expanded cork
Black cork panels (expanded) are basically used as thermal and acoustic insulators . In its manufacture, the cork agglutinates without the need of any chemical additive, with its own resin (suberine) by means of a cooking system that is what gives it the roasted tone. We can find in the market panels measuring 1000 × 500 mm with thicknesses ranging from 20 to 60 mm. I leave this link where you can see the manufacture of expanded cork.
We must clearly differentiate the black cork from the so-called white cork , as it is often called expanded polystyrene, EPS or polyspan, since this is a plastic material, a resin, which has nothing to do with a natural product.
When I delve deeper into the natural cork, I have to tell you that I was surprised that most of its characteristics constitute a clear constructive advantage. It has been really hard for me to find arguments against this material, although some also exist. Next, I indicate the advantages and disadvantages of its use in construction.
Advantage
Ecological . It is a 100% natural and 100% recyclable product since its imputrescible composition and resistance to atmospheric variations gives it an unlimited life cycle. Thus, it can be transformed at the end of its first use into new raw material for later use.
Waterproof . It admits its placement in humid areas such as bathrooms and basements (this characteristic is what makes its use suitable for bottle corks).
Breathable . This property gives it a unique feature as a climate regulator that avoids condensation as it isolates. And, at the same time, it allows perspiration between the two insulated surfaces.
Optimum insulation . Very resistant to high temperatures and droughts. Its honeycomb structure (whose natural function was the protection of the living parts of the tree) gives it great resistance to the passage of heat and cold. In addition, the cork maintains identical insulating properties throughout its life cycle.
Acoustic and vibration isolation . It is this same cellular cellular structure, which acts as a buffer in the transmission of sound waves providing a great attenuation of noise and absorbing shock waves.
Resistant to pressure and understanding . It does not deform easily. And, when it does, it has a great capacity to recover the initial volume (as long as it has not been perforated) since its cells are arranged in the form of radial rows without leaving gaps between them. Something that, together with the presence of air inside them, provides a great mechanical resistance.
Very light material . What, in addition to facilitating its placement, allows its use on light structures and ceilings.
Great adhesion to smooth surfaces due to the holes in the cells that make it up.
Nonflammable . This characteristic caught my attention since I believed that precisely his behavior to the fire was not suitable. Only after watching these videos whose links I share, I have convinced myself otherwise: comparison with polystyrene , and fire proof on cork board .
Protection capacity . The soft surface of a cork floor can act as a kind of cushion that provides a certain amount of protection when someone accidentally trips and falls. This makes it a great option for children's rooms and for older residents prone to falling.
Natural repellent . The suberine, which is the main component of cork, works as a natural insecticide since it has the property of repelling small bugs and insects. This makes cork soils resistant to the growth and colonization of these organisms and, therefore, contribute to increasing the health of an environment.
Disadvantages
Cork floors can be scratched more easily than wooden floors . And that is why its use is not recommended when you have dogs or cats at home, since the scratch marks may be irreparable.
Nor are they indicated in spaces where they receive a direct and continuous light from the sun, since the exposed parts will modify their tonality that ends up fading .
Cork floors, like wooden floors, do not work well with radiant floor heating because, as mentioned above, they offer great thermal insulation that prevents heat from radiant pipes from entering the environment.
The origin of cork
After these meager arguments against, and the innumerable advantages described above, I think that, like me, you may be wondering why is this material not used more widely? The explanation, as almost always, is economical. And in this case, not because of the price of the material itself, but because of the term to make the investment of a cork oak plantation profitable, so there is no abundance of entrepreneurs who want to embark on this business.
It takes a cork oak between 30 and 35 years to form its crust and the first layer of cork that is extracted, the sausage, is not economically profitable. From that moment, every nine or ten years you can already make 'the peel', where a much more formed cork is extracted, thicker and with more applications in the industry. If we add to this the fact that more than 70% of the cork produced is used for caps, what is left for the rest of the products (insulations, coatings and agglomerates) is clearly insufficient.
A group of cork oaks with the bare trunk after the cork
However, we trust that the use of this excellent material will continue to be generalized in construction. And, furthermore, to continue researching for the achievement of products such as Cork Wise cork flooring as a result of an R&D project of the Portuguese company Amorin, which has received the prize for innovation in architecture and construction (Innovation Award for Architecture and Construction).
Finally, I leave you the example of a project by Anonymous Architects® and Paulo Teodósio carried out in 2007, La Casa Cork . And I remind you that the PEFC Forest Certification is a guarantee that the raw material of the cork products comes from a cork oak managed in a sustainable way, controlling all intermediate production processes, through the chain of custody.