How much attic insulation, R-value ?

Old 04-17-04, 03:36 PM
Paul Doucette
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How much attic insulation, R-value ?

I live in Massachusetts. I am going to use my attic space as storage, so there will be a floor. Most of the attic space is open (no floor, joists exposed). The floor joists are 2" x 6". There is loose-fill insulation in there now, but it looks like some more could be added to get it up to 5" -6" inches. As I understand it, this will give me a R-19 rating. I was hoping for a R-30, but that does not seem possible.

My questions are:
Is the R-19 rating sufficient for my attic given where I live?
If not, is there any other way to get me a better rating?

I could possibly sister some 2" x 10" joists to my existing 2" x 6" joists, which would give me an extra thickness to my loose-fill insulation and give me a R-30 rating, but I would rather avoid doing that.

Help !!!

Old 04-17-04, 04:39 PM
willywhy's Avatar
Join Date: Jun 2001
Location: N. E. Illinois
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Befor sistering the 2x10's have an inspection to see if the walls and other supports will hold the added weight of plywood flooring, etc.
There is a more dense batt insulation that provides more r value, but you will need to remove the loose fill.
Old 04-17-04, 06:08 PM
Ed Imeduc's Avatar
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Location: Mountain Williams Missouri
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For where you are a R-30 or better is what you should have Thats about 9 1/2". So like what do you want to put up there .Like was said will the ceiling rafters take the load of 2X10 and plywood?? do you have trusses there????Dont know how big the attic is but what about doing only a small part with the 2X10 and plywood Insulation under it and the rest a good R 30 on top of what you have now. Dont for get foam rafter vents so the air can get up from the over hang of the home to the roof vents. you dont want to put insulation with paper on it on top of what you have now. R 19 needs 6" and you dont want to compress it at all.


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