Ring beam - Insulation for 5cm U-shaped shell

Hello,

the construction-accompanying quality control noticed that our ring beam only has insulation of 5cm. He said that this is a thermal bridge.

I have attached a picture for you.

The proposal was now 8cm and, as insulation, a higher thermal conductivity class. I have informed the general contractor accordingly and he wanted to discuss it with the structural engineer.

I would never have noticed this myself, and if it is really true, then the QAQC has already been worth it.

What do you think?

Thanks for your feedback.

Is the ring beam already finished or are you still in the preparation phase? The insulation value of the ring beam consists of 2x Poroton, 1x insulation, and 1x reinforced concrete. I also have only 5cm of insulation for two different versions each.

We have not signed the construction contract yet, so it can still be adjusted. Would you say that you have a thermal bridge?

To what extent reinforced concrete has good insulation I cannot judge at all.

We have not signed the construction contract yet, so it can still be adjusted. Would you say that you have a thermal bridge?

To what extent reinforced concrete has good insulation, I cannot judge at all.

No idea if that will be a thermal bridge. I don't think so. Probably not an optimal U-value, but condensation water probably won't form. And yes, reinforced concrete also has an insulating value. Poor but present. DDR panel buildings also consisted only of 20cm concrete. Plus now your insulation and the Poroton brick, you won't be heating up the environment.

Would you say that you have a thermal bridge?

To what extent reinforced concrete has good insulation I cannot judge at all.

And yes, reinforced concrete also has an insulation value. Poor but present.

Reinforced concrete has a lambda value of about 2.1 W/mK, so it can practically be "overmeasured" when calculating thermal protection.

GDR prefabricated buildings also consisted of only 20 cm concrete.

The prefabricated buildings from the 60s to the 90s largely consisted of concrete, but of aerated concrete and the insulation value of this component was not bad at all. Other parts were problematic.

What is right about is that the 5 cm insulation (thermal conductivity group 035) is not uncommon and for the overall thermal protection at this point the inner and outer Poroton shell must also be taken into account. For this, your general contractor, if he made such a drawing, also made a calculation from which the U-value for this component emerges.
Without changing the statics, the WLG of the insulating material or the insulation material can be changed, since it has no load-bearing function; this is assumed by the ring beam.
Highest insulation effect approved for installation in this location would be Resol rigid foam boards (WLG 022), but they are a bit more expensive.
But even with the normally used XPS 035 or 036 boards you will not have problems with condensation at this point.
Purely mathematically, you will be better off with Resol boards and 8 cm, but for me at least in terms of insulation thickness, a sufficiently oversized ring beam would be more important.

The prefabricated buildings from the 60s to the 90s were largely made of concrete, but made of aerated concrete and the insulation value of this component was not bad at all.

I have lived in various prefabricated buildings for 20 years and have also drilled into exterior walls. I have never come across anything like aerated concrete there. Are you sure?