Kimhof00
2024-11-04 07:54:45
- #1
Hello everyone,
we are gut-renovating our house which we bought (built in 1969). In May, we renewed the roof. Since a new roof covering was more than necessary, we decided on a 100mm exterior rafter insulation. Between the rafters, we insulated with 120mm glass wool towards the heated upper floor. In the collar beams, there is 40mm glass wool from 1969. We will also install a new roof hatch with a folding ladder.
The attic is unheated, has a roof window, and there is 23mm tongue and groove boarding on the floor. The attic is intended to be used as a storage room.
In the attic, we also wanted to insulate between the rafters with 120mm glass wool. Installing a vapor barrier airtight there is almost impossible due to all the bracing under the ridge beam (see photo).
If I run the vapor barrier down to the middle purlin and stick it there firmly, then I am trapping moisture in the attic, right? Since the attic is not ventilated daily and only rarely accessed. The vapor barrier in the heated upper floor below runs from the knee wall along the roof slopes over the collar beams to the wall (see drawing).
1: What is the correct procedure here with the vapor barrier and between-rafter insulation in the attic?
I also read that holes should be drilled in the exterior rafter insulation above the middle purlin and not insulated there, so air can circulate. That should not matter for the stored Christmas decorations etc.
2: Or would it be more advisable to lay a walkable insulation on the tongue and groove boarding? And completely do without the between-rafter insulation? Is drilling holes through the exterior rafter insulation still necessary then?
Many thanks for your answers.
Best regards
we are gut-renovating our house which we bought (built in 1969). In May, we renewed the roof. Since a new roof covering was more than necessary, we decided on a 100mm exterior rafter insulation. Between the rafters, we insulated with 120mm glass wool towards the heated upper floor. In the collar beams, there is 40mm glass wool from 1969. We will also install a new roof hatch with a folding ladder.
The attic is unheated, has a roof window, and there is 23mm tongue and groove boarding on the floor. The attic is intended to be used as a storage room.
In the attic, we also wanted to insulate between the rafters with 120mm glass wool. Installing a vapor barrier airtight there is almost impossible due to all the bracing under the ridge beam (see photo).
If I run the vapor barrier down to the middle purlin and stick it there firmly, then I am trapping moisture in the attic, right? Since the attic is not ventilated daily and only rarely accessed. The vapor barrier in the heated upper floor below runs from the knee wall along the roof slopes over the collar beams to the wall (see drawing).
1: What is the correct procedure here with the vapor barrier and between-rafter insulation in the attic?
I also read that holes should be drilled in the exterior rafter insulation above the middle purlin and not insulated there, so air can circulate. That should not matter for the stored Christmas decorations etc.
2: Or would it be more advisable to lay a walkable insulation on the tongue and groove boarding? And completely do without the between-rafter insulation? Is drilling holes through the exterior rafter insulation still necessary then?
Many thanks for your answers.
Best regards