The "U-value" is a measure of the thermal performance or heat transfer rate of a building material, such as insulation or windows. It quantifies how effective a material is at insulating against heat loss or heat gain. In the context of construction and energy efficiency, a lower U-value indicates better insulation properties.

Here's how the U-value works:

1. Definition: The U-value, also known as the thermal transmittance, is measured in watts per square meter kelvin (W/m²•K) or British thermal units per hour square foot degree Fahrenheit (Btu/h•ft²•°F). It represents the amount of heat energy (in watts or Btu) that passes through one square meter (or square foot) of a material when there is a temperature difference of one degree Kelvin (or one degree Fahrenheit) between the inside and outside surfaces.
   
   
2. Lower U-Value, Better Insulation: A lower U-value indicates that a material is a better insulator because it allows less heat to pass through. For example, a U-value of 0.2 W/m²•K means that 0.2 watts of heat energy will pass through each square meter of the material for every degree Kelvin of temperature difference.
   
   
3. Application: U-values are commonly used in building construction to assess and compare the thermal performance of different building components, such as walls, roofs, windows, doors, and insulation materials. Builders and architects use U-values to make informed decisions about which materials to use to achieve energy-efficient and well-insulated buildings.
   
   
4. Physical & mechanical cork material properties
   
   The cork oak is the world's only cork oak species producing such thick bark of uniform structure, which spontaneously grows as covering over dying tissue. The bark of this tree - in everyday language, "cork" – is a constantly necrotic tissue formed during the life cycle of these trees by the continually expanding cross-section of their trunks and branches. It is visible under a microscope that this tissue is made up of closed dead micro-cells with the appearance of fourteen-sided polyhedra; the intercellular spaces are completely filled with a gaseous mixture almost identical to the air environment surrounding the tree. In 1cm3 of this tissue there are more than 40 million such fourteen-sided cells. Their chemical composition includes: suberin (45%), lignin (27%), cellulose and polysaccharides (12%), tannic acid (6%), wax (5%) and other substances (5%).
   
   

High Durability - Highly durable and flexible coating to prevent cracking.

Super Adhesive - When it’s on, it stays on covering a range of surfaces, including steel.

Patch Repairs - Patch repairs possible (avoids costly or time-consuming whole-wall re-rendering).

Thermal Performance - Strong thermal insulator and reduces thermal bridges.

Good Sound Insulation - Acoustic insulation goes hand in hand with thermal insulation. Our cork product coating can absorb up to 38dB of noise, giving occupants of roadside properties a more peaceful life.

Fire Resistant - (Euro-class B safety rating), water resistant and breathable (this helps prevent mould and damp, gives people a healthier living and working space).

Natural & Sustainable - Now with 40% more cork content, our cork product comes from a natural product and causes no permanent damage to the environment. Improved thermal performance – The ultimate thermal regulator, which can reduce fuel costs, because of the added cork content.

Improved quality - With more cork content, the product makes for a fuller, better-quality finish.

More colour options - Now available in 28 colours as standard to better suit British tastes, with the option of bespoke tinting for larger orders

Faster application - Improved drying times help get the job done faster.

Longer Warranty - 25-year product warranty