ᐅ Thermal Insulation of a Gable Roof

Hello everyone,

I want to insulate our roof and have already calculated a few different options, both in terms of U-values and costs. Unfortunately, I now have several variants and can’t decide.

Here are the basic details:

- House built in 1950
- Roof from 2008

Roof structure:
- Tiles
- Battens
- Counter battens
- Delta foil (vapor permeable membrane)
- Rafters 120mm x 75mm (5 inches x 3 inches)

Option 1:
- Insulation wool WLG035 120mm (5 inches) between the rafters
- Vapor barrier
- Battens
- Drywall

Option 2:
- Insulation wool WLG035 120mm (5 inches) between the rafters
- Battens
- Insulation wool WLG035 50mm (2 inches) between the battens
- Vapor barrier
- Drywall

Option 3:
- Boards 30mm x 160mm (1 inch x 6 inches) fixed sideways to the rafters
- Insulation wool WLG035 160mm (6 inches) between the rafters/boards
- Vapor barrier
- Battens
- Drywall

Option 4:
- Boards 30mm x 160mm (1 inch x 6 inches) fixed sideways to the rafters
- Insulation wool WLG035 160mm (6 inches) between the rafters/boards
- Battens
- Insulation wool WLG035 24mm (1 inch) between the battens
- Vapor barrier
- Drywall

Maybe someone can take a look and share their opinion – I’m grateful for any tips. Perhaps I have fundamentally planned something wrong. I can’t assess the moisture values.
I’m not looking to make the house an energy-saving miracle according to energy regulations, but some insulation is better than none.

Thank you very much.

Option 2

v.g.