We bought a prefabricated house a few years ago. It has a first floor and an attic as living space. Above that is the peaked roof at about standing height.
The insulation is currently installed on the top ceiling of the attic. The peak floor is not insulated, and has only a foil under the tiles (probably trickle protection). I would now like to lay OSB boards on the top floor. To do this, I have a lathing before to allow air circulation under the plates to the insulation.
When checking the structure of the insulation, I came across the following. The ceiling of the attic is gypsum board, then up follows a vapor barrier (I assume because it is metal-coated paper) and on top lies the insulation wool. Now the question arises whether I can insulate the attic and if so, how would the structure or a connection to the vapor barrier be made? Do I have to open and fold up the roof insulation and barrier for this?
That you want to lay the OSB boards at a distance from the insulation makes sense. However, I would leave a few larger gaps at the boards so that the air can really circulate.
I think your plan is critical. The attic would then be insulated but still unheated. All around closed with foil, so no air circulation. Logically, the air will stand there and very likely become a problem at some point. You would then have to design this open to the OG, but open an existing insulation level I would think twice. As it sounds it is also still very easy to renew or strengthen the insulation if necessary. From such a thing I would keep open for me