Basements, Attics and Crawl Spaces - Attic Insulation
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Weather
11-02-09, 03:54 PM
Can I use paper-backed R19 pink fiberglass insulation for my attic?
I have 2x6 attic joists and a bunch of R19 paper-backed pink fiber glass insulation. It is listed for use on exterior walls, but since I already have it and it should fit "perfectly" in my joist bays, I would like to use it.
What concerns me is that most attic insulation applications call for the paperless variety. However, I have never seen an explanation of why non-backed insulation would be preferable to paper-backed insulation in an attic application.
I have 2x6 attic joists and a bunch of R19 paper-backed pink fiber glass insulation. It is listed for use on exterior walls, but since I already have it and it should fit "perfectly" in my joist bays, I would like to use it.
What concerns me is that most attic insulation applications call for the paperless variety. However, I have never seen an explanation of why non-backed insulation would be preferable to paper-backed insulation in an attic application.
Bud9051
11-02-09, 04:23 PM
Hi Weather, and welcome to the forum.
The kraft facing makes it easy to staple into place for walls or ceilings, but since the kraft may bolck some moisture, it should be on the warm side of the insulation. If you already have it and want to sue it, just remove the paper and you will be fine. As to what constitutes a vapor barrier and why you need one, here is a link for some info.
Energy Savers: Vapor Barriers or Vapor Diffusion Retarders (http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11810)
BSD-012: Moisture Control for New Residential Buildings — (http://www.buildingscience.com/documents/digests/bsd-012-moisture-control-for-new-residential-buildings?full_view=1)
Bud
The kraft facing makes it easy to staple into place for walls or ceilings, but since the kraft may bolck some moisture, it should be on the warm side of the insulation. If you already have it and want to sue it, just remove the paper and you will be fine. As to what constitutes a vapor barrier and why you need one, here is a link for some info.
Energy Savers: Vapor Barriers or Vapor Diffusion Retarders (http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11810)
BSD-012: Moisture Control for New Residential Buildings — (http://www.buildingscience.com/documents/digests/bsd-012-moisture-control-for-new-residential-buildings?full_view=1)
Bud
GBR in WA
11-02-09, 06:10 PM
As Bud said, for the initial application with the paper down towards the room, it will work. The next layer should be unfaced and installed perpendicular to the ceiling joists. Make certain to seal any ceiling holes or gaps around plumbing pipes, fans, electrical boxes and wrap the fan ductwork with insulation and a vapor barrier, as the article Bud gave points out. Use fire-proof material around B-vents (gas appliance exhaust), chimneys, and no insulation within 3" of non-insul. can lights. Do not cover knob and tube wiring. Use baffles and rigid foam board near the exterior walls to keep the air supply to the ridge vents.
Be safe, Gary
Be safe, Gary