ᐅ Installing vapor barrier membranes in overlapping layers—any experiences?
Created on: 5 Oct 2017 22:17
C
CharlieHarperC
CharlieHarper5 Oct 2017 22:17Hi!
Does anyone have experience with installing multiple layers of humidity-variable vapor retarders one after the other?
Idea:
In our attic, there is already insulation installed with an aluminum foil facing on the interior side. I want to keep it as it is. The aluminum facing is reduced in its vapor diffusion resistance (SD value) from about 1500 to around 5 by using a textured roller; does anyone have data on what minimum "breakdown" or treatment level is needed to achieve this?
On top of this, a humidity-variable membrane will be fixed to prevent any material from the external insulation being carried inward by wind or vibrations caused by other factors. The material previously used is now considered carcinogenic, which is another reason to effectively seal it from the inside. The insulation performance is not too bad; I believe I read it has an R-value around 0.35. Then, an additional insulation layer will be installed, finishing with a final humidity-variable membrane.
Long story short, I would like to upload further details as a PDF, but unfortunately, that’s not possible here; according to the U-value page in the PDF file, it should work. Any critical remarks on this concept?
Does anyone have experience with installing multiple layers of humidity-variable vapor retarders one after the other?
Idea:
In our attic, there is already insulation installed with an aluminum foil facing on the interior side. I want to keep it as it is. The aluminum facing is reduced in its vapor diffusion resistance (SD value) from about 1500 to around 5 by using a textured roller; does anyone have data on what minimum "breakdown" or treatment level is needed to achieve this?
On top of this, a humidity-variable membrane will be fixed to prevent any material from the external insulation being carried inward by wind or vibrations caused by other factors. The material previously used is now considered carcinogenic, which is another reason to effectively seal it from the inside. The insulation performance is not too bad; I believe I read it has an R-value around 0.35. Then, an additional insulation layer will be installed, finishing with a final humidity-variable membrane.
Long story short, I would like to upload further details as a PDF, but unfortunately, that’s not possible here; according to the U-value page in the PDF file, it should work. Any critical remarks on this concept?
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