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attic insulation need help


pogi1234's Avatar
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Join Date: May 2007
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05-15-07, 09:00 AM   #1  
attic insulation need help

hello, i'm thinking of hiring a contractor to insulate my attic someone told me that a blow- in fiberglass or a blow-in cellulose is good but which is better fiberglass or cellulose? what's the advantage/disadvantage? thanks for any help u can give. (Mel, NJ)

 
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Ed Imeduc's Avatar
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05-15-07, 09:10 AM   #2  
I like the cellulose better . I think it does a better job. Also you can check. Fiberglass dont burn BUT it will melt right away and let a fire get through. the
cellulose Will just turn black and not burn or melt away. Count the bags they use on your home. So you get the R you pay for. So many sq ft per bag.

 
adamplghtg's Avatar
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05-15-07, 06:31 PM   #3  
Yes Ed is deffinetly right! Cellulose is much better than fiberglass(both blow and batts).

http://cellulose.org/ has a lot of info on it and its benifits compared to fiberglass.

 
cs1992's Avatar
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05-16-07, 03:00 PM   #4  
I'm not so sure that test/website was "unbiased."

Regardless, my attic has cellulose insulation and quite frankly, I am dubious about its long term effectiveness for one reason: settling.

When first installed, it was nice and fluffy. This is what you want from insulation. (Think about a big, fluffy, down sleeping bag...more space between the feathers traps more air)
Although it was certified R-30 at the time, I doubt that it is still measures up to that level of effectiveness. Although I have not measured the exact amount of settling, it is surely noticeable (in appearance).

If I had to do it all over again, I would increase the amount of cellulose in my attic by 50%.

 
adamplghtg's Avatar
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05-19-07, 06:35 PM   #5  
When you spray cellulose you are supposed to spray enough to make up for the settleing. For example, you may blow 16" knowing its going to settle to 15" or about. The bags of cellulose are sold(or supposed to be sold) at the settled thickness and should say how much loose fill you need to achive a certin settled R-value. Its not going to continue to settle over the years. Once it reaches a certin point, it will stop. And yeah, there is always some bias regardless of where you get your information but some of the studies on that site were done by 3rd parties.

 
jodyfitz's Avatar
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05-22-07, 04:55 PM   #6  
If you want to do the insulation right, Spray foam is the answer. Cost is high but it works. Doesn't settle or sag. Spray to the roof deck will stop radiant heat also.

 
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