Insulation of old buildings on natural / sandstone cellar

Hello everyone,

since this is my first post, I would like to briefly introduce myself.
My name is Rouven, I am 24 years old and come from the south of BW.

After much back and forth, I was allowed to buy my "dream house" the week before last.
It is an old villa with 450 sqm of living space from 1939 on a 4500 sqm plot.
The villa is built on a sandstone cellar, which stands on rammed clay with a natural floor. Part of the flooring is covered with natural stones (possibly bricks?). The large vaulted cellar has no flooring. Currently, there is a lot of moisture and partly mold in the cellar. I assume it was hardly ventilated.

I plan to subject the villa to a major renovation starting in August. This means - new hipped roof including insulation, doors, windows, wall and floor coverings as well as all the wiring will be renewed. There will also be some changes to the floor plan.

Although I am quite experienced in industrial construction, the conversion or renovation of an old building is new to me. I hope to be able to count on your help!

My architect said after the first preliminary discussion that, due to the "breathing" sandstone cellar, the walls must never be insulated. Otherwise, it would be damaging to the substance. He envisions insulation of the roof structure. Heating would be done via radiators with a heat pump.

The house is supposed to have decentralized ventilation.

Now my question: Do you see it the same way? I want to professionally renovate the house from the ground up so that everything fits when moving in. Investing so much money and not insulating the house in today's times sounds a bit strange to me. What is your opinion?

Many thanks in advance,

Regards!

I think the basement does not need to be insulated, or is there living space in it as well? I would either insulate the basement ceiling and/or (if the room height allows) the ground floor floor. Moisture in the basement is best regulated with dew point-controlled fans. Are there even windows to ventilate? Is your architect also an energy consultant? Otherwise (or anyway) I would bring one on board. Our first energy consultant was also an architect and recommended some terrible solutions for energy-efficient renovation, so I am skeptical of the combination. And if you want to use KFW funding, you need one anyway. Can be found via the KfW homepage.

Thank you for the answer,

The basement is partly outdoors. The open part consists of a separate apartment, which I would also like to rent out. As far as I know, there are no windows in the "house basement." I am referring to insulating the walls on the ground floor.

I will take care of the energy consultant, thank you!

Oh, I assumed in my tips that it was a purely utility basement. Unfortunately, I don't know what the best solution is in your case.

Specialist for old building renovation inquiries. An architect who wants to heat an "ungedämmetes" house with a heat pump and radiators does not sound like it.