ᐅ Interior Insulation of Basement Wall in Stairwell – Condensation Issues

Hello everyone,

We are currently renovating the entire house and adding comprehensive insulation. The basement will remain uninsulated on the exterior; only the basement ceilings will be insulated.

The basement is mostly unheated.

The house has two floors plus a basement, with the stairwell being heated. Each floor and the basement have a door leading to the stairwell.

In the basement stairwell, we currently have some cold bridges.

Wall 1 faces the ground and is not insulated so far. Wall 2 leads to the storage room, which is cool. The floor also remains uninsulated.

The wall that runs along the stairs leads to a cold laundry room in the basement. This wall cannot be insulated due to the staircase, not even from the other side.

We would like to insulate Wall 1 and Wall 2, ideally with minimal thickness (e.g., PUR/PIR). Otherwise, we use mineral wool or wood fiber insulation throughout the house.

What should we consider here? Our energy consultant said this is too complicated, especially regarding condensation, and suggested involving a building physicist (because of just two walls?!).

Does insulating here make sense, and if so, how should we proceed?

Thank you very much!