Additional insulation in the Ytong basement (36 cm)

... are you asking about the foundation slab? .... or is your question specifically about the exterior walls surrounded by earth, and then it plays a crucial role which heated rooms in the basement are directly adjacent to exterior walls that are backfilled with earth ...

... it is about the exterior walls. The rooms adjacent to the exterior walls with earth are: bathroom, bedroom, guest room, utility room, and laundry room... So actually all except the living/dining room!

... ..So actually all except the living/dining room!

.. well then I would create a heat demand analysis with a temperature profile and the company Ytongg or Hebel could help you with that ...

.. well then I would create a heat demand analysis with a temperature profile and the company Ytongg or Hebel could help you with that ...

Thank you very much for the tip. I have already contacted the company Ytongg and I was also told there that I do not need additional insulation.

Nevertheless, I have now decided to add 6cm. I feel better about it and the extra cost is not a big deal...

Best regards

I have now decided to add 6cm after all.

.. please .. add where? and how do you keep the thermal insulation dry in the ground? .. you are building a basement for living spaces out of aerated concrete that is 70% underground!

I assume it is crucial on which ground/floor the basement is founded. In many cases, aerated concrete is definitely the wrong choice. We are on a slope and have no pressing water, etc.... Soil surveys, structural engineers, and others have all done their work, so this is not the issue here. The selected insulation is a perimeter drain board and complies with the DIN.

Best regards

Hello,

I assume it depends on the type of ground/floor the basement is founded on. In many cases, aerated concrete is certainly the wrong choice. We are on a slope and have no pressing water, etc.... Soil survey, structural engineer, and others have all done their work, so this is not the issue here. The selected insulation is a perimeter drain board and complies with the DIN standard.

Your question about additional insulation (everyone first thinks of the classic ETICS) caused some confusion; at least for me. Your announcement today that it is a perimeter insulation brings some clarity - but (again for me) raises new questions.

I really can hardly imagine that Ytong® would recommend that you omit perimeter insulation for a partially earth-contacting residential basement - or better said, a lower ground floor (UG) in your case. I worked with aerated concrete for a long time and know that it does not require additional insulation (ETICS) at a thickness of 36.5 cm. However, if the basement rooms are heated, the situation looks a bit different. Of course, it also concerns thermal protection => "According to the state building codes, habitable rooms in basement floors are permitted if moisture protection and thermal protection are ensured. For heated rooms, the energy saving ordinance must be observed" but also the protection of the masonry against the soil.

In short, I do not understand why you have to pay for a - for us a matter of course - perimeter insulation of the earth-contacting exterior walls in the basement when it is not part of your provider’s standard?

Rhenish greetings