Cork is a 100% natural insulating material.
Cork boards and cork granules insulate both thermally and acoustically, are moisture repellent and are not affected by mice or termites.
Cork does not burn autonomously and therefore has a fire-retardant property (class B2 according to DIN 4102). Because cork is a natural product, no chlorides, cyanides or other toxic gases are released during combustion.
Cork also has a very favourable ageing coefficient. This means that the insulation value of cork hardly decreases over time, in contrast to various alternatives. Cork is naturally water-repellent. This means that the insulation value or thermal conductivity cannot increase when the material becomes wet and that it cannot rot under the influence of moisture and poor ventilation.
Cork also insulates acoustically. The speed of sound slows down considerably in cork, which attenuates the prevailing noises.
The lambda value λ (W/mK) is the insulation value of a material. The lower the lambda value, the better the material insulates. The lambda values of most bio-ecological insulation materials fluctuate between 0.035 and 0.040 W/mK.
Insulation value of some insulation materials:
Insulation materials from renewable raw materials λ
Flax 0,038 W/mK
Hemp 0,040 to 0,042 W/mK
Paper flakes 0.039 W/mK
Wood fibre 0.037 to 0.040 W/mK
Cork 0,038 to 0,040 W/mK
Sheep's wool 0.035 W/mK
Insulation materials from mineral raw materials λ
Perlite 0.051 W/mK
Vermiculite 0.053 W/mK
Cell glass 0.040 to 0.050 W/mK
Silicate foam granules 0.040 W/mK
Glass wool 0.032 to 0.040 W/mK
Rockwool 0.035 to 0.040 W/mK
Insulation materials from petrochemical raw materials λ
EPS 0.033 to 0.042 W/mK
XPS 0.029 to 0.038 W/mK
PF 0.020 W/mK
PUR 0.023 to 0.032 W/mK
PIR 0.023 to 0.032 W/mK
The diffusion resistance number μ (mu) indicates the vapour permeability of a material. It indicates how much more difficult the water vapour passes through the material in question than through the air. You can see in the table below that the insulation materials from renewable insulation materials have a small mu value and are therefore vapour permeable, and the insulation materials from petrochemical raw materials have a large mu value and are therefore vapour tight. You should therefore preferably use insulation materials from renewable raw materials.
Diffusion resistance number μ (mu) of some insulation materials:
Insulation materials from regrowable raw materials μ
Flax 1 to 2
Hemp 1 to 10
Paper flakes 1 to 2
Wood fiber 1 to 5
Cork 5 to 30
Sheep's wool 4 to 5
Insulation materials from mineral raw materials μ
Cellular glass infinite
Silicate foam pellets 3
Glass wool 1
Rockwool 1 to 5
Insulation materials from petrochemical raw materials μ
PUR 50 to 185
Heat storage capacity
At homes, the use of materials with a high heat storage capacity (such as brick, sand-lime brick, natural stone, etc.) is a major advantage. The heat storage capacity c (J/kgK) or inertia of a building material is the capacity of the material to store heat and release it again in a delayed manner. It therefore has a regulating effect.
Heat storage capacity c of some insulation materials:
Insulation materials from renewable raw materials c
Flax 1550 J/kgK
Hemp 2100 to 2500 J/kgK
Paper flakes: 1940 to 2150 J/kgK
Wood fibre 2000 to 2100 J/kgK
Cork 1670 J/kgK
Sheep wool 1720 J/kgK
Straw 2100 J/kgK
Insulation materials from mineral raw materials c
Perlite 900 J/kgK
Vermiculite 900 J/kgK
Cell glass 840 J/kgK
Silicate foam granules 800 J/kgK
Glass wool 800 J/kgK
Rockwool 800 J/kgK
Tackling moisture problems sustainably
Many facades nowadays are affected with time. Moisture causes the paint to come loose from the facades because the excess ambient moisture cannot be removed by ventilation. Until now, the only option was to repaint regularly to renovate the decorative aspect of the facade, without solving the moisture problem or improving the thermal insulation of the building.
The buildings covered with spray cork are given a special colour and appearance, and the thermal defects are also corrected.
This makes the inside of the building for a healthier environment thanks to the elimination of thermal bridges that cause internal condensation and the formation of mould, saltpetre, etc., which are very harmful to a building and its occupants. Due to scarce or poor insulation, many buildings are heated too much, which has consequences for the owners of the buildings. Renovation with spray cork is an efficient means of achieving the ideal temperature in buildings, with fewer hours of heating, since, depending on the geographical area, differences of 5 to 8° C between the outside and inside temperatures are obtained.
Cork will never assume a negative temperature (even if it freezes) and will never heat up at temperatures above 30°C.