I'm wondering if anyone out there has come across specific language for the attachment of fiberglass insulation over an unconditioned crawl space.  I realize there are various ways to accomplish proper installation where the insulation material makes contact with the floor diaphragm.  Personally I prefer to see the use of nylon twine as a means of attachment and I'm wondering if anyone happens to know of any recommended spacing guidelines for the attachment points of a zig zag pattern of twine when used for support of floor insulation.

Views: 2829

Replies are closed for this discussion.

Replies to This Discussion

That all makes sense. Having spent the last 20 years building and remodeling homes and only the last 4 concentrating on building science and weatherization, I am still trying to figure out what many of you veterans have already learned. I thank you for the responses and your time.

See section 3.2 of the ENERGY STAR TERC guidelines

From the "Retrofit Workforce Guidelines" (which are still in critical care & unavailable at the moment - but from my review)

7.36 Accessible Floors (between conditioned & unconditioned space) – personally not the best choice down south, but that’s for another day

  • 7.36.1: Sealing the floor system will be completed before installing – very nicely stated
  • 7.36.2: Insulation will be installed in contact with subfloor without gaps, voids, compressions, misalignments, or wind intrusions & If kraft-faced batts are used, they will be installed with kraft facing to subfloor  - also very nicely stated (though kraft is worse thing you can use)
  • 7.36.3: Batts will be secured with physical fasteners TO ensure insulation remains in contact with subfloor – the only issue is that they also need to minimize compression while still keeping it from sagging

I assume you're aware of the latest Building Science rant from Dr. Joe in which he argues against the requirement that insulation be in contact with subfloor (I excerpt it here at http://homeenergypros.lbl.gov/forum/topics/another-irreverent-whine...), and will try to get this changed in the next IRC code revision.

But why do you say that Kraft facing is a problem? It meets the IRC guideline for a 1 perm vapor retarder.

Thanks Robert & yes I am but that doesn't apply to the here, now or the question posed. 

As for the question about the kraft - no matter where you are at, if one is going to use such a product the last thing you want is water being trapped against it & the subfloor whether it is from moisture in the air, over active cleaners, plumbing leaks, or water splashed from tubs, showers, or sinks. Maybe you guys have less issues up north, but down here unfaced FG is bad enough & the kraft style seemingly just makes it worse

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network.

Latest Activity

Colin Genge's video was featured

Passive House Testing Webinar (Feb 13, 2014)

We covered: - Measuring air leakage in a tight house; - New passive house testing equipment; - Powered flow hoods for accurate measurement of HRV ERV flow ra...
2 hours ago
Colin Genge posted events
9 hours ago
John Nicholas replied to Sean Lintow Sr's discussion Duct Testing - is a change in order? in the group Best Practices (Residential)
"Yes,  I was connected to the AH cabinet.  I find it easier in this area, given the common…"
11 hours ago
Colin Genge replied to Kim Tanner's discussion Blower Door Applications Guide in the group Multifamily Buildings
"This is a great guide that anyone testing with multiple fans should get hold  of. "
12 hours ago
Colin Genge added a discussion to the group Multifamily Buildings
Thumbnail

Just posted a lot of Multi-Family oriented blower door videos.

Just posted a lot of Multi-Family oriented blower door videos. Everything to do with Multi-Fan…See More
12 hours ago
Colin Genge joined Norm Bourassa's group
Thumbnail

Multifamily Buildings

For too long there has been relatively little EE focus on multifamily, but some new programs have…See More
12 hours ago
Colin Genge replied to Sean Lintow Sr's discussion Duct Testing - is a change in order? in the group Best Practices (Residential)
"I would assume you tested that high air leakage from the equipment cabinet and not on a flex…"
12 hours ago
Colin Genge replied to Sean Lintow Sr's discussion Blower Doors & Methods Used in the group Best Practices (Residential)
"For those of you who need  a Tectite report, FanTestic's report Generator is powerful…"
12 hours ago

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service