ᐅ Interior insulation with udiin, experiences

Of course, there is condensate or moisture from the indoor air due to vapor pressure within the wall.

However, a vapor barrier or vapor retarder—whether a foil or liquid membrane—is simply detrimental for an internal insulation system that is fully glued, reinforced, and plastered over its entire surface. It absolutely has no place in this construction (regardless of the fact that you simply cannot install it there).

You are still withholding the explanation....

Moisture can be absorbed and circulate within the insulation and adhesive layers of fully bonded interior insulation systems. Through vapor pressure equalization, the moisture can then be released back into the interior space.

These systems do not require a vapor barrier or vapor retarder.

Additionally, ventilation (windows and doors open) is necessary to ensure that any excess moisture is eventually removed to the outside.

Well, the fact is that interior insulation for a detached house without heritage protection is simply out of the question.

Adding a few centimeters (cm) of insulation won’t make the space significantly darker, and as already suggested, you can enlarge the opening outward.

There are also highly efficient insulation solutions that add very little thickness, such as vacuum insulation panels. These are not cheap and can be difficult to install.

Just to mention: The insulation value of those Udiin panels at the thickness you mentioned is minimal. Even with just 2cm (1 inch) of mineral wool on the exterior wall, you get better insulation.
If you add a slim 100mm (4 inches) layer on the outside, you already meet the energy-saving regulations and will achieve a significant improvement.

Here are some numbers, calculated with a 36.5cm (14.5 inches) Poroton wall from the 1970s.
U-value without insulation: 0.547 W/m²K
U-value with your planned interior insulation: 0.463 W/m²K
U-value with 10cm (4 inches) insulation, thermal conductivity 0.035 W/mK: 0.213 W/m²K

Ibaaa schrieb:
In a fully bonded interior insulation system, moisture can be absorbed and circulate within the insulation and adhesive layers. Through vapor pressure equalization, the moisture can then be released back into the room.

For this to work as you expect, you would need to have regularly very warm, dry air inside the room. How do you achieve this? Why does moisture still accumulate in the insulation under these conditions? And what role does the (fully applied) adhesive play in all of this?

Ibaaa schrieb:
... It is important with interior insulation that there are no cavities in the adhesive layer, as condensation can form there, which leads to mold.
….

@ Herr Dr Hix: Interior insulation is not rocket science! And the insulation system that the OP wants to use doesn’t require a vapor barrier or vapor retarder.