My 1950’s vintage ranch home has about 3 1/2″ of loose insulation in
the unfinished attic floor over the living spaces below. I know more
insulation is necessary, but I’m also wondering about a vapor barrier.
Ideally the barrier should be against the heated surface or towards the
living space. Do I need to remove the existing insulation or do I place
more insulation directly over the existing? If so, should a vapor
barrier be used at all? I do plan on placing baffles in the eaves and
just had multiple passive vents put in the roof when
the shingles were removed/replaced this past summer. Due to the hip
roof design, a ridge vent was not a good option.
Thanks for your opinions/help.
Rocky River, Ohio
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Michael Hindle explores the efficacy of deep energy retrofits and discusses essential considerations for effective climate mitigation.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
I'm interested in hearing what answers you get on this one. I get called into service, by family usually, to look into similar issues.
I like a lot of the stuff written up by these guys (link) - I'm glad someone finally took the time to look at the vapor issues scientifically:
http://www.buildingscience.com/
Sorry for my non-answer, but maybe it'll bump your question for additional input from the gang.
The need for and location of a VB depends on your geographic and climatic location
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
The 3.5" of insulation may have a value of 7-12 depending on the material. If not contaminated with bat/rodent droppings, leave as is. Learn about air leakage control (airsealing) and airseal the attcic where necessary. Add R35 blown cellulose to attic. Weatherstrip and insulate the hatch well.
There is a slim chance you have vermiculite insulation, given the age of the house.
There are some concerns with it: see this page at the EPA web site for pics and discussion of the best practices: http://www.epa.gov/asbestos/pubs/insulation.html#Do
Hi,
Before you put more insulation in, I would pull it away locally where there are penetrations from below for lights or pipes or wires, and seal these up with the Polyurethane foam in a can. Its much easier to do this with 3 inches of insulation than with 15 inches. Also a good time to seal up the joints on any heating ducts that run through the attic with duct mastic. After doing the above, I blew in about 6 inchs of cellulose over my 8 inches of loose fiberglass. This was just a one afternon task, and no problems.I hate to push a Tauton book on the Tauton web site, but Bruce Harley's Insulate and Weatherize is my bible -- its really good.Gary
http://www.BuildItSolar.com