attic ceiling insulation

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  #1  
Old 12-30-08, 03:07 PM
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attic ceiling insulation

i put a peak (gable) on a flat roof that was over my garage. the garage was converted to living space years ago and it is part of the living room. since installing the roof peak, i now have additional attic space. i want to insulate the ceilings and walls of it. what R-rating do i use for the ceiling and walls? what kind of insulation do i use for both of them?
 
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  #2  
Old 12-30-08, 04:32 PM
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To estimate your insulation needs, we need to know the climate where you live.

Here is some reading for you:
Welcome To Home Energy Magazine Online

HNY
Bud
 
  #3  
Old 12-30-08, 06:55 PM
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i live in long island, ny. if i read it right, it saying not to insulate the attic ceiling. i have done some ceiling repair in another area in the attic that is finished, and there is insulation. so what do u suggest?
 
  #4  
Old 12-31-08, 06:10 AM
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Tell us how you are going to finish this off. The peak now sits on the flat roof, which should have been insulated and sealed. The peak has a gable end wall and rafters and should have some soffit venting. Typically the soffit venting would allow cold air to vent unwanted heat from the bottom of the roof deck up to gable vents or a ridge vent. Which vent style do you have? Your options would be to insulate a knee wall, the slope, and a small flat ceiling. OR insulate and finish the slope from the eves all the way to the gable vent or the ridge vent depending.

In NY you are going to need a lot of insulation and typically the 2x6 rafters with some vent space won't give you enough room. Thus a combination of rigid and fiberglass, or pad down the rafters to be very thick so you can get an R-38 or more in there.

Pictures would help. photobucket.com and post the link over here.

Worked for several years with a long island refugee. He now lives in NJ in a house I built.

HNY Bud
 
  #5  
Old 12-31-08, 04:09 PM
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i want to insulate from the slope from the eves all the way to the ridge vent. my house is 54 years old. i have been reading up on this and a lot of my research is saying to install baffels from just above the soffit vents to just below the ridge vent in the roof. considering the age of the house and from other areas of the attic, i do not see any baffels and i doubt they used them. are they necessary? i was thinking of just getting rolls of R-38 & staple the paper faced part to the rafters. i guess the paper part would be facing me?
 
  #6  
Old 12-31-08, 05:33 PM
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The problem is r-38 is about 12 inches of fiberglass and your rafters are about 6 inches. Then there is the one to two inches of air gap between the insulation and the bottom of the roof deck, that is what the baffles are for. If you want to leave out the baffles, the thickest insulation you can put in and still have an air gap, would be high density r-15 3.5" fiberglass. To increase the r-value, you will have to add rigid over the fiberglass or pad out the 2x6 and use the thicker fiberglass.

Of course I'm assuming 2x6's. Maybe you have larger rafters. But achieving R-38 or 49 isn't easy or cheap. But then again as we saw a couple of months ago, neither is energy.

HNY
Bud
 
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