Clamp insulation, floor slab, frost/thaw cycle, foil materials?

Hello everyone,

I have a very important question for us and unfortunately received various answers on site.

I would like to insulate our roof or the top floor ceiling.

We have a classic "Kaffeemühle" house from 1937 with a hipped roof, so 4 almost equal roof surfaces.
The roof structure (see sketch) is as follows: roof beams, roofing felt (partially coated with bitumen from the inside), in other parts foil, battens, and then concrete tiles.

The special feature is that the attic room was practically hung into the roof like a box.

I can directly access 1.5 roof surfaces as well as the entire attic, the others could only be “stuffed” from the attic.
The attic room was constructed with plasterboard, which was nailed to a stud framework or directly to the roof beams. The floor in the attic thus partly consists of plasterboard, and on the other part from the top view of a wooden paneling (pine).

The goal of the insulation as an optimum: insulation fitted between the beams or only the “top floor ceiling”.

Now to my questions:
1. Can I glue the holes in the roofing felt and install a clamp fleece? Or stuff it in from above (here I obviously don’t know the condition of the roofing felt that is behind it).
2. If I only insulate the top floor ceiling. What do I do here, put foil on and then wool? What do I do with the gaps at the edges that reach downwards? Just stuff them so it doesn’t draft anymore? Will condensation possibly form here?

I am just a little afraid that the roof structure will rot away. However, insulation is necessary because last year everything up there froze, including the computer LCD ;-)

I would be very grateful for answers and support!!!

Best regards
Arndt

Hi,

have you ever considered completely renewing the roof? It all sounds somehow very makeshift, amateurishly cobbled together.

If the roof is covered with roofing felt, you must not place insulation against it. Roofing felt is relatively airtight, which means you will most likely get mold problems. The best option is to insulate the upper floor ceiling and install a vapor barrier towards the heated room. If the attic space is to be insulated, you must definitely ensure sufficient ventilation.

Regards