Wood
Cork
Linoleum
Biological tested
NATwood

Cork is the name given to the bark of the cork oak tree. This magnificent tree has been a characteristic feature of the landscape of Portugal for thousands of years, but it is also found in other countries of the western Mediterranean. Unlike other trees, the cork oak does not suffer damage when its bark is peeled off. Cork is thus a raw material that grows again meaning it is entirely environmentally compatible.

Before a tree can be ready for harvesting, however, it must mature for a period of at least 25 years. Further harvests are then possible every 9 to 10 years. It is only the bark from the trunk and the thicker branches of the cork oak that are peeled away by hand. Some 20 % of the bark is left on the tree to protect it from drying out. The corking process requires a great deal of experience and is only done by specialists.

The cork is only removed down to the reddish mother layer that must on no account be damaged. Slowly new cork grows below this (annually approx. 1.5 - 4 mm). The cork oak flourishes for up to 250 years and thus supplies a thoroughly environmentally friendly over a period of many years.

• Processing
• The raw material
• Characteristics

Processing

A rough sorting process is made after the harvesting of the bark and it is stored for about. 6 months to dry and stabilise. The cork sections are then placed in boiling water at the works. This kills off any insect pests hidden in the bark. The process also removes tannin from the cork. The material is now soft and elastic and it loses its cylindrical form. After the boiling process, the cork must again ripen in darkened storage rooms at a specific temperature.

The good quality cork sections are cut into strips, their width is the length of bottle corks. The cork cutter’s art is to be able to produce as many perfect bottle corks as possible from a single raw material piece.

The blanks that remain and the poorer quality cork is ground into cork meal of various corn sizes and densities. This granulate cork is sorted and boiled again and pressed into blocks with the help of fixing agents. These blocks are measured out into the required dimensions for the production of cork floors.

Differentiation is made between single layer and double layer cork floors. The single layers, also referred to as solid cork, consist of a highly compressed pressed cork. The double layer has a base in pressed cork over which a decorative laminate is placed to give it a significantly improved appearance.
 

The raw material

The outer cortex of the cork oak has a unique honeycomb structure composed of tiny cells. Each cell is a 14-sided polyhedral the entire inner cell cavity of which is filled with air. The characteristics of cork result naturally from the structure and chemical composition of its extremely strong and flexible cell membranes, which are both watertight and airtight.

Each cubic centimetre of cork consists of 30 - 42 million cells.

The density of cork is very low, between 480 and 520 kg/m3, since some 89 % of this tissue is of a material in gas form,
this explains the difference between its volume and its weight.

Characteristics

• Can be greatly compressed and elastic
• Excellent insulation and fire retarding
• Extremely hard wearing
• Undergoes no changes as a result of high temperature variations
• Outstanding soundproofing
• Virtually indestructible
• Pleasant warmth to the feet

Elasticity:

The cell membranes are very flexible, they are responsible for the fact that the cork can be greatly compressed and is elastic.

Impenetrable:

Cork is liquid and gas-tight due to the presence of suberite (a complex compound of fatty acids and powerful organic alcohol).

Insulation:

The value of cork is increased by its very low conductivity of temperature, of sound and vibrations. This results from the fact that gas formed elements are sealed into impenetrable chambers and are insulated from each other by a fluid insulating material.As a result of this cork shows some of the best insulating properties both thermal and acoustic of any natural material.

Hard wearing:

Cork is also remarkably hard wearing and has a high friction coefficient. It suffers less wear or damage than other hard surfaces as a result of collision or friction because of the honeycomb structure of the SUBERITE surface.

Allergies:

Cork does not absorb dust and thus does not cause allergies and does not represent a risk to asthma sufferers.

Fire retarding:

Naturally fire retarding. Flame does not spread on cork, nor does it release poisonous gases when burning.

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