Ideal Board Thickness – Good Thermal Insulation

The thickness of the insulation panel in the naturbo interior insulation system with 60 mm was chosen very consciously. Two factors played a particular role:

1. Ratio of insulation effect to space loss

Those who insulate their house from the inside must always make a compromise between loss of space and the quality of thermal insulation. The additional insulation effect decreases the stronger a wall is already insulated. The following table illustrates this, using the soft wood fibre board used in the naturbo system with a thermal conductivity of 0.042 W/(m•K):

Insulation Thickness	Thermal Insulation
10 mm	4,2 W/m²K
20 mm	2,1 W/m²K
30 mm	1,4 W/m²K
40 mm	1,1 W/m²K
50 mm	0,8 W/m²K
60 mm	0,7 W/m²K
70 mm	0,6 W/m²K
80 mm	0,5 W/m²K
90 mm	0,5 W/m²K
100 mm	0,4 W/m²K
110 mm	0,4 W/m²K
120 mm	0,4 W/m²K

From the table it becomes clear ...

that with low insulation thicknesses (10 – 50 mm) every inch of additional insulation brings a significant improvement in the quality of the insulation effect.
that with large insulation thicknesses (80 – 120 mm), the additional insulation thickness brings almost no additional insulation effect.
that in a medium insulation thickness range (50 – 80 mm) there is the best ratio between insulation thickness and insulation effect.

For this reason, an insulating panel thickness of 60 mm was used for the naturbo interior insulation.

2. Building Physical Simplicity

As already mentioned, the formation of dew water requires special attention in the development of an interior insulation system. Computer programs can calculate the amount of moisture to be expected at which insulation thickness. The following applies: the thicker the insulation, the more complicated the building physics.

The plate thickness of the naturbo interior insulation system was determined on this basis in such a way that the system is still very tolerant with regard to the dew water and at the same time achieves a good insulation effect.