Insulation of the adjoining room in the garage

Hello everyone,

I have diligently searched through the posts but unfortunately couldn't find an answer that fits my case. :(

We have built an adjacent room onto the garage next to the residential building. The exterior garage walls consist of 11.5 cm facing brick - 2 cm air gap - 17.5 cm solid concrete block.
The adjacent room shares one longitudinal side with the residential building (17.5 cm Poroton of the residential building exterior wall - 16 cm mineral wool - 2 cm air gap - 11.5 cm solid concrete block of the adjacent room wall). I have attached a sketch.
Except for the southern exterior wall of the adjacent room, which is itself the 17.5 cm solid concrete block exterior wall of the garage, all walls are 11.5 cm solid concrete block.

The roof currently consists of an EPDM membrane laid on top, tongue-and-groove boards, and then spruce beams.

My goal for the adjacent room is to reliably prevent frost in winter and extreme heat in summer. Clothes and canned goods are to be stored there.

My questions:

1. Is roof insulation with 16 cm mineral wool sufficient for this?
2. If not, which material would you recommend for the interior insulation of the walls?

Exterior insulation is unfortunately not an option here. If wall insulation is necessary for my goals, this is probably simply a design flaw.... =(

Thank you very, very much!

The problem is that you have no heat source in the room. You can insulate as much as you want, but if it is cold for a week in winter, the room will still cool down. A passive house at least has people and electrical devices as heat sources. Your storage room has nothing at all.

Thank you for your reply! So a freezer is definitely going to be placed in the room. It borders the heating room of the residential building along one lengthwise side. Additionally, it is connected to the room by a steel door. I thought that all together would at least be a passive heating for the room, which could prevent frost. Or?

On one lengthwise side, it adjoins the heating room of the residential building. Additionally, it is connected to the room by a steel door. I thought all of that together would at least already be a passive heating for the room that could prevent frost. Or?

Whether a freezer is sufficient, no idea. But if the heating room of the house "heats" an external room, in my eyes that would be a faulty house insulation – in other words, nothing should actually pass through there.

A modern freezer consumes around 120 kWh of electricity per year, depending on its size. Most of this is used in summer when the ambient temperature is warmer. In winter, when the room is around 0 degrees, it hardly needs to provide cooling performance. Even with well below 1 kWh/day, nothing significant can be achieved, even with [Passivhausstandard].

Insert frost guard - done.