Which insulation to use for plastering over a roller shutter box

Hello everyone,

sorry in advance... I already accidentally posted this request in the window section and only noticed after creating the post. I think I am better off here in the insulation section:

We would like to plaster over the roller shutter boxes on our extension so that the boxes are not visible in the end.

The box depth according to the manufacturer is 12 cm, with a plaster corner profile additionally mounted on it.
So I estimate that the box then has a depth of about 13.5 cm.
The box will be mounted directly on a wooden beam (our extension is built in timber frame construction).

How thick does the insulation need to be, which is attached next to the box, so that I can plaster over the box?

Is a 12 mm insulation sufficient at the yellow-marked points in the attachment?

Sorry, maybe my question is totally stupid, but I really have no idea how much insulation I need to use on the extension to get the 13.5 cm box plastered over.

Many thanks in advance.
Best regards
Oli

Hey, is the beam to which the box is attached flush with the surrounding wall? Or is it set further inward?
What does your energy plan/planner say about the minimum insulation you have to use?

However, if the box is to be installed as you write, the insulation must be at least as deep as your plaster angle, so 13.5 = 14cm insulation. Above the plaster angle (onto the housing) a plaster carrier (Styrodur). Then fiberglass mesh, spackle, and plaster as usual.