ww_chris1984
2021-08-28 23:22:49
- #1
A very good evening to everyone!
My girlfriend and I are currently having my grandparents' house renovated in order to move into it in the fall. It is a matter close to our hearts, and we are making every effort in all aspects to get the best out of the existing building fabric ([Baujahr 1952 Massivhaus mit Schwemmstein wurde als Haus für Flüchtlinge nach dem WWII gebaut]).
The next major step is the conversion of the attic. Since we are both more or less laypersons, I am currently quite unsure and hope to get help and assessment from the community here.
We are receiving different statements from various parties regarding the procedure and I am totally uncertain about how to proceed.
It is about the insulation of the pitched roof from the inside. A combined between- and under-rafter insulation is to be installed (is that the correct way to say it?). According to the craftsman, the following setup makes sense and will be implemented by the selected company: between-rafter insulation, then a vapor barrier, then under-rafter insulation, and on top an OSB board. Finally, drywall panels. The insulating material is Knauf WLG32 mineral wool. The vapor barrier is a product called Knauf Insulation LDS FlexPlus.
My actual question is the following. The craftsmen say that the insulation layers must be ventilated from behind. So for example, with 14 cm insulation there must be 16 cm of space. The building materials dealer, a friend who is an architect, and another craftsman in my circle of friends said that this is no longer common today and that with 14 cm insulation 14 cm of space would be sufficient.
How do you assess this? Can this be answered in general? Are there relevant arguments against the general setup? I have read about quite different possible structures here.
I do not want to presume to tell a craftsman how to do his work as a layperson, but I think my uncertainty is understandable. Also, I would simply like to understand it.
I would lose 4 cm of space on each pitched roof side. That is a lot, and if it is not necessary, I would like to avoid it.
If further information is needed for a better assessment, I will gladly provide it.
Thank you very much in advance for your support.
My girlfriend and I are currently having my grandparents' house renovated in order to move into it in the fall. It is a matter close to our hearts, and we are making every effort in all aspects to get the best out of the existing building fabric ([Baujahr 1952 Massivhaus mit Schwemmstein wurde als Haus für Flüchtlinge nach dem WWII gebaut]).
The next major step is the conversion of the attic. Since we are both more or less laypersons, I am currently quite unsure and hope to get help and assessment from the community here.
We are receiving different statements from various parties regarding the procedure and I am totally uncertain about how to proceed.
It is about the insulation of the pitched roof from the inside. A combined between- and under-rafter insulation is to be installed (is that the correct way to say it?). According to the craftsman, the following setup makes sense and will be implemented by the selected company: between-rafter insulation, then a vapor barrier, then under-rafter insulation, and on top an OSB board. Finally, drywall panels. The insulating material is Knauf WLG32 mineral wool. The vapor barrier is a product called Knauf Insulation LDS FlexPlus.
My actual question is the following. The craftsmen say that the insulation layers must be ventilated from behind. So for example, with 14 cm insulation there must be 16 cm of space. The building materials dealer, a friend who is an architect, and another craftsman in my circle of friends said that this is no longer common today and that with 14 cm insulation 14 cm of space would be sufficient.
How do you assess this? Can this be answered in general? Are there relevant arguments against the general setup? I have read about quite different possible structures here.
I do not want to presume to tell a craftsman how to do his work as a layperson, but I think my uncertainty is understandable. Also, I would simply like to understand it.
I would lose 4 cm of space on each pitched roof side. That is a lot, and if it is not necessary, I would like to avoid it.
If further information is needed for a better assessment, I will gladly provide it.
Thank you very much in advance for your support.