Renovate old roof - construction year 70s

Hello,

I or rather my family and I are considering renovating our roof ourselves. We are currently looking for a master roofer who will be available to us with his expertise and help us seal the roof windows and chimneys. We might have already found one. However, this should not be the main topic here. This is more about a second opinion.

I have added pictures as attachments. Due to the current construction method and my previous research, only a combination of above-rafter insulation and between-rafter insulation is possible. Since we prefer not to completely renovate the attic apartment. We are aware that the windows need to be raised.

I am mainly interested in materials you can recommend. Whether it is insulation for the between-rafter insulation or the above-rafter insulation. Or which vapor barrier should be used best. To be honest, I am not so interested in "ecological" materials, because according to initial research, they do fulfill their purpose but are quite expensive. Other materials are supposedly just as good and also cheaper. Or which wood wool lightweight panel should be used, etc.

I would also like to know which installation method you would recommend for the vapor barrier. Would you recommend placing the vapor barrier between the individual rafters (12 - 14 cm wide) and fastening it with small battens? How should the vapor barrier best be installed in the area of the gutter so that no moisture can form there? We were thinking of "careful" cutting, gluing, and nailing / stapling it on.

The roof terrace / balcony will also be renovated. Oh, and later a photovoltaic system will be installed on the balcony side.

Thanks in advance for your feedback, if any will come at all :D

Honestly? You seem to be a total layman.

So first

Master roofer looking to share his expertise with us

talk to him once you have found him.

It actually gets quite interesting in the occupied attic. Installing the vapor barrier there without interfering with the current ceiling cladding will be challenging – it is supposed to be on the inside (warm side) and especially properly connected so that no warm air gets into the insulation and makes everything wet there.

I am mainly interested in materials that you can recommend here.

There are none that I would not recommend. Wood fiber has its advantages for summer heat protection. Is noise an issue for you?

Due to the current construction and my previous research, "only" a combination of insulation above the rafters and insulation between the rafters is an option.

Why?

P.S. Practically nothing can be seen in the exterior photos.

Correct, that is why there are questions here as well as all the videos/websites about roof construction and the master roofer.

For example, I watched videos from "ENERGIESPARKOMMISSAR." Most recently the following videos from him: Roof insulation - from the outside / between and above rafter insulation / airtightness.

There he addresses the maximum insulation layer in between-rafter insulation. And that a combination is usually the best option in old buildings. To avoid completely rebuilding the roof. Since the roof is not used anyway, you don’t have to insulate as much with above-rafter insulation.

The vapor barrier could then be "installed" as in the attachment. But here I am more interested in finding out all the possibilities to make sure the master roofer is not telling us nonsense.

What are the dimensions of the rafters?

If you now attach heavy insulation made of wood fibers between and over the rafters, the load capacity could be exceeded, especially if photovoltaic modules are also supposed to go on later.

So it is better to first check the statics of the rafters or contact a structural engineer.

What are the temperatures like in the finished part on hot summer days?
Mineral wool or polystyrene bring little long-term benefit there, and with wood fibers you might have the structural problems described above.
In that case, a climate split unit on the balcony is a better solution, especially with your own photovoltaics.