S
Stickst0ff22 Dec 2020 18:06Hello to all fellow builders.
I have built myself before and am familiar with the concept of insulation from the living space to the attic (insulation wool between rafters -> vapor barrier nailed from below -> cross battens -> drywall ceiling).
Now, a friend has bought a house that is about 100 years old. The ceiling construction from bottom to top (cold roof) is as follows: plaster-reed composite (reed nailed), floorboards laid perpendicular to the rafters -> guiding layer of floorboards/boards between rafters on the lower boards (each 20mm (¾ inch) thick) -> cavities filled with slag/straw mix.
My plan was to remove the plaster/straw ceiling, empty the cavities, remove the boards lying parallel to the rafters, and replace everything with insulation wool. Then attach counter battens to the lower boards, install a vapor barrier, and finally suspend a new drywall ceiling. However, there have been ongoing discussions about this. Some suggest leaving the plaster-reed ceiling in place, only removing the slag material and replacing it with wool, then installing the drywall ceiling.
My goal, in my opinion, is to relieve the roof structurally and update the old insulation methods. Personally, I find the option with the vapor barrier the most energy-efficient. Unfortunately, I’m unsure if I need to remove the bottom layer of boards to correctly install the vapor barrier and wool system, or if this layer of boards can remain in place (they are butted edge to edge). Or should the old ceiling even stay entirely and only the slag part be replaced by wool, omitting the vapor barrier completely?
I hope I explained it clearly enough.
Do you have any experience with this, or are there specific regulations regarding this?
I would greatly appreciate constructive help and advice.
Best regards
I have built myself before and am familiar with the concept of insulation from the living space to the attic (insulation wool between rafters -> vapor barrier nailed from below -> cross battens -> drywall ceiling).
Now, a friend has bought a house that is about 100 years old. The ceiling construction from bottom to top (cold roof) is as follows: plaster-reed composite (reed nailed), floorboards laid perpendicular to the rafters -> guiding layer of floorboards/boards between rafters on the lower boards (each 20mm (¾ inch) thick) -> cavities filled with slag/straw mix.
My plan was to remove the plaster/straw ceiling, empty the cavities, remove the boards lying parallel to the rafters, and replace everything with insulation wool. Then attach counter battens to the lower boards, install a vapor barrier, and finally suspend a new drywall ceiling. However, there have been ongoing discussions about this. Some suggest leaving the plaster-reed ceiling in place, only removing the slag material and replacing it with wool, then installing the drywall ceiling.
My goal, in my opinion, is to relieve the roof structurally and update the old insulation methods. Personally, I find the option with the vapor barrier the most energy-efficient. Unfortunately, I’m unsure if I need to remove the bottom layer of boards to correctly install the vapor barrier and wool system, or if this layer of boards can remain in place (they are butted edge to edge). Or should the old ceiling even stay entirely and only the slag part be replaced by wool, omitting the vapor barrier completely?
I hope I explained it clearly enough.
Do you have any experience with this, or are there specific regulations regarding this?
I would greatly appreciate constructive help and advice.
Best regards
S
Stickst0ff22 Dec 2020 19:26PS: I just noticed that I posted this in the wrong section, but somehow I’m unable to delete the post.
Similar topics