External wall insulation with ETICS. How many cm of rigid foam boards are reasonable?

Hello everyone,

we are not quite sure how many cm of insulation with the rigid foam boards makes sense.

One builder says that the exterior wall accounts for 40% of the total exterior area of the house and recommends (in addition to reinforcing the roof insulation) also strengthening the exterior insulation.

The background was that we actually wanted to replace the 17.5 cm Poroton bricks with ETICS from the construction specification with 36 cm solid brick or with 24 cm aerated concrete with ETICS. Our builder (Heinz von Heiden, Hesse) advised us to save the surcharge on aerated concrete and rather invest in stronger insulation for the exterior walls. Is Heinz von Heiden's objection correct?

In the construction specification, the insulation boards of the exterior walls have a thickness of 16 cm and the exterior wall has a U-value of 0.19.

With an additional cost of about 2,500 euros, we would get a 24 cm exterior insulation with a U-value of 0.14...

Now we are having talks with several builders and the one from Helma thinks that is nonsense. Only the roof is important and should be reinforced, as the interior space of the house decreases with thicker boards.

Question: How do you see the question of the THICKNESS of the exterior insulation with rigid foam boards (no alternatives, it is really only about the thickness of the boards and whether the efficiency gain justifies the surcharge)

Thank you in advance to all helpers

Hello,

...we are not quite sure how many cm of insulation through the rigid foam boards makes sense.

What does "makes sense" mean? Minimal transmission heat losses, energy saving ordinance requirement, or economical insulation thickness? Additionally, it should be questioned whether "rigid foam boards" are the best choice.

...Question: How do you see the question of the THICKNESS of the external insulation with rigid foam boards (no alternatives, it is really only about the thickness of the panels and whether the efficiency gain justifies the extra cost)

Already here it becomes clear that a well-founded basic investigation or concept development has probably not taken place.
With symptoms of illness, ask 10 doctors. Result: 15 illnesses and 20 therapies. However, non-binding and excluding any liability.

Best regards

Our developer (Heinz von Heiden, Hessen) advised us, Many thanks in advance to all helpers

Here the insulation topic will probably be rather unimportant... there are quite different and more important considerations for you... It is quite astonishing how people still think about certain developers in 2010...

Hello,

It is amazing how, in the year 2010, people still think about certain developers...

...Ostrich?...

Kind regards