Attic Insulation - vapor barrier???
I'm sorry if I didn't find the answer posted in the forums but here is my question:
I have a ranch with 2-3 inch bats for insulation. Lots of holes and open spots. I'm planning on adding some insulation and I'm wondering what the best option is?
I don't have a vapor barrier - From what I understand unless the vapor barrier is "seamless" it is almost useless. Is there a reason to try and add poly between the rafters, or use faced bats?
Or am I better off pulling up the small amount of insulation I have, air sealing as much as possible, and blow insulation in?
We are in NE ohio.
Thanks for any suggestions,
Vapor barrier is surface measured, you are confusing the two: http://www.greenbuildingadvisor.com/...cience-podcast
Faced batt will work, not to worry about full coverage of the paper facing: http://www.insulating-products.com/p...lation_FAQ.pdf
Air seal first, then cellulose: http://www.diychatroom.com/f98/bigge...ulation-90438/
Thank you for the thoughtful reply - I appreciate suggestions backed by evidence.
If i understand correctly - provided I have well painted moisture repelling ceilings - any air leaks will contribute far more moisture contamination from air transport then the threat of moisture from diffusion.
"If i understand correctly - provided I have well painted moisture repelling ceilings - any air leaks will contribute far more moisture contamination from air transport then the threat of moisture from diffusion."------ exactly. Plus, with cellulose, a v.b. is not required: http://www.applegateinsulation.com/C...id=249418&fd=0
Air-sealing importance: http://www.jlconline.com/cgi-local/v...170a32100a05c7
The stack effect: http://www.wag-aic.org/1999/WAG_99_baker.pdf
Confusion about diffusion: http://www.buildingscience.com/docum...bout-diffusion
This should clinch it for you, Dan, lol, 1/3 quart vs. 30 quarts: http://www.buildingscience.com/docum...apor-retarders
Not many customers do but with all of GBRs reading, you got it nailed down.
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