Thermal insulation

Thermal insulation of wood wool

The thermal insulation of wood wool is excellent: by nature wood offers a good thermal insulation. Heraklith offers three types of combi wood wool boards with which you can fine-tune the thermal insulation to the exact thermal requirements.

Depending on the building application it is important to choose a solution and combine the wood wool boards with either a core of rock mineral wool, grey EPS or PIR.



EPS insulation Heratekta

Wood wool boards with grey EPS have a thermal performance which is up to 25% better thanwood wool with white EPS.

Thus, a comparable thermal insulation performance can be achieved with a thinner wood wool board.

Combi wood wool boards with grey EPS insulation ensure optimal thermal insulation of living and working areas. An investment in good thermal insulation results in lower energy consumption, higher comfort and a reduction in CO2 emissions.

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PIR insulation Herafoam

Use wood wool boards with a rigid PIR insulation foam in projects where you have to achieve a high thermal performance with a limited thickness of insulation. With a thickness of 155 mm you can achieve a RD value of even 6,40 m2.K/W

This wood wool board is ideal for concrete ceilings and walls in renovation projects, but of course you can use these wood wool boards in new constructions as well.

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Rock mineral wool Tektalan A2

With our Tektalan we combine wood wool boards with rock mineral wool. These wood wool boards not only offer a good thermal performance but also a good fire classification (A2) and acoustic insulation for walls and ceiling.   

The fire-resistant properties of Tektalan are excellent with a fire resistance of 180 minutes. The Heraklith Tektalan A2 wood wool boards can act as a heat shield. The integrity of a construction is guaranteed longer in the event of a fire.


Thermal insulation: terminology


The RC-value is the heat resistance value of the total construction. This is a sum of all Revenue values ​​of all materials, corrected with, among other things, the influence of thermal bridges (such as wood and metal).



RD is a declared calculation value, which is also called a Rdeclared value. The RD value indicates how great the heat resistance of the insulation material is. This RD only covers the stand-alone product. RD is indicated in the unit m2

RD   [m2 K/W] = thickness [m] / λ [W/m.K]


Rrevenue value

The Rrevenue value is the calculation value of the heat resistance of each layer of which the structure is constructed, including correction factors.

U value

The U- value (former K-value) indicaties the thermal conductivity of a construction and is the inverse of the R value (U = 1/R).
The better the insulation package, the lower the U-value.

Formula: U value = λ value / thickness insulation.

The U value expresses the amount of heat that passes per second, per m² and per degree of temperature difference between one side and the other side of a wall or ceiling construction. The U value is also called heat transfer coefficient.

The value indicates the degree of heat conduction of a wall: a high U-value means a thermally poorly insulating wall, a low U-value means a thermally well insulating wall. The unit for the U-value is W / (m² · K).


Excellent thermal performances with Heraklith wood wool boards

Are you looking for excellent thermal insulation with wood wool cement sheets, based on EPS insulation? Then you are at the right place at Heraklith. Our insulation experts help you choose the right wood wool products, in accordance with the fire safety requirements and acoustics of the project.


Interested in seeing how we solved the challenges for other architects and constructors? Just download our case study to learn more. 


The best thermal insulation

Choosing the best thermal insulation is not easy. Acoustical and fire safety-related building requirements are added to that. Do you want to know which thermal insulation material works best for your project? Feel free to contact us.