ᐅ Insulation of an Adjacent Room in the Garage

Hello everyone,

I have searched through the posts diligently but unfortunately couldn’t find an answer that fits my situation. 🙁

We have built an additional room onto the garage that is adjacent to our house. The garage’s exterior walls consist of 11.5cm (4.5 inches) facing bricks – 2cm (0.8 inches) air gap – 17.5cm (7 inches) concrete blocks.
The added room shares one long wall with the house (17.5cm (7 inches) Poroton bricks of the house’s exterior wall – 16cm (6.3 inches) mineral wool – 2cm (0.8 inches) air gap – 11.5cm (4.5 inches) concrete blocks of the additional room wall). I’ve attached a sketch.
Except for the southern exterior wall of the additional room, which is the 17.5cm (7 inches) concrete block exterior wall of the garage itself, all walls are 11.5cm (4.5 inches) concrete blocks.

The roof currently consists of an EPDM membrane on top, boarding underneath, and then spruce beams.

My goal for the additional room is to reliably prevent freezing in winter and extreme heat in summer. It will be used to store clothes and canned goods.

My questions:

1. Is roof insulation with 16cm (6.3 inches) mineral wool sufficient for this?
2. If not, which material would you recommend for interior insulation of the walls?

Exterior insulation is unfortunately not an option here. If wall insulation is necessary to achieve my goals, it’s probably just a planning mistake... =(

Many, many thanks!

The problem is that you don’t have a 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 appliances as heat sources. Your storage room has nothing at all.

Thanks for your reply!
So, a freezer will definitely be placed in that room. One of its longer sides borders the heating room of the house. Additionally, the room is connected by a steel door. I thought that altogether this would at least serve as a passive heating for the room, which could prevent freezing. Or not?

rauferchen schrieb:

One of its long sides borders the heating room of the house. Additionally, it is connected to that room by a steel door. I thought all this together would at least serve as some sort of passive heating for the room, which could prevent freezing. Or not?

Whether a freezer is enough, I have no idea. But if the heating room of the house is "heating" an adjoining external space, in my opinion, that indicates faulty building insulation — meaning, nothing should really be passing through there.

A modern freezer typically consumes around 120 kWh per year, depending on its size. Most of this energy is used during the summer when the ambient temperature is higher. In winter, when the room temperature is around 0°C (32°F), it hardly needs to provide any cooling power. Even with a passive house standard, it is difficult to get below 1 kWh per day.

Just install the frost guard – done.