ᐅ OSB boards used as a vapor retarder, with a suspended ceiling installed below
Created on: 5 Jan 2018 09:12
C
Crimson
Good morning everyone,
I wanted to gather your experiences on the following topic:
In our new build, the roof was completed before Christmas. Now, the installation of the insulation between the rafters and the vapor retarder / vapor barrier is coming up.
Our carpenter, in consultation with the master mason, suggested the following (the carpenter has reportedly had good experience with this approach): insulation between the rafters using mineral wool and a continuous OSB panel as the vapor retarder. For this, the sloped partition walls in the roof space were not built all the way up to the rafters, but left a gap of 1-2cm (0.4-0.8 inches), allowing the OSB panels to be installed continuously across the entire interior slope of the roof (which I think is good in principle, as it reduces weak points caused by sealing work on the masonry).
My question is: what do you think about this, or what are your experiences with using OSB panels as a vapor barrier? It seems opinions differ, and I lack firsthand experience within my circle.
For the interior finish, we would like to install recessed spotlights in some areas. For this, the ceilings in the hallway and bathroom will need to be lowered. I would prefer not to screw drywall directly onto the OSB panels, as cracks might develop over time. It shouldn’t be a problem to fasten a metal subframe to the OSB panels to accommodate the electrical installations, correct?
The rest of the OSB panels will be plastered.
Best regards,
Crimson
I wanted to gather your experiences on the following topic:
In our new build, the roof was completed before Christmas. Now, the installation of the insulation between the rafters and the vapor retarder / vapor barrier is coming up.
Our carpenter, in consultation with the master mason, suggested the following (the carpenter has reportedly had good experience with this approach): insulation between the rafters using mineral wool and a continuous OSB panel as the vapor retarder. For this, the sloped partition walls in the roof space were not built all the way up to the rafters, but left a gap of 1-2cm (0.4-0.8 inches), allowing the OSB panels to be installed continuously across the entire interior slope of the roof (which I think is good in principle, as it reduces weak points caused by sealing work on the masonry).
My question is: what do you think about this, or what are your experiences with using OSB panels as a vapor barrier? It seems opinions differ, and I lack firsthand experience within my circle.
For the interior finish, we would like to install recessed spotlights in some areas. For this, the ceilings in the hallway and bathroom will need to be lowered. I would prefer not to screw drywall directly onto the OSB panels, as cracks might develop over time. It shouldn’t be a problem to fasten a metal subframe to the OSB panels to accommodate the electrical installations, correct?
The rest of the OSB panels will be plastered.
Best regards,
Crimson
K
Knallkörper5 Jan 2018 19:37In other words: Either the top is heated, so no vapor barrier is needed at the bottom. Or the top is cold, then you need a vapor barrier at the bottom and the top must be vapor permeable, for example with tongue-and-groove boards.
K
Knallkörper5 Jan 2018 19:43No. That is not possible.
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