Insulating attic floor

But it is not necessary to call in a professional. Simply place wool in between, and tongue and groove boards on top. The foil is not needed because 1. the wool releases moisture upwards and can do so, and 2. an airtight layer is not necessary here.

By forced ventilation I meant that there is minimal air circulation in the attic. Otherwise, moisture accumulates there.

But there is no need to call in a professional. Just put wool in between, and roofing boards on top. You don't need the foil because 1. the wool releases moisture upwards and can do so, and 2. an airtight layer is not necessary here.

By forced ventilation, I meant that a minimal air circulation exists in the attic. Otherwise, moisture accumulates there.

So far, there has been no forced ventilation either. The attic is dry and dusty. I can't imagine that there won't be enough circulation after laying it down.