Need more insulation...question


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Old 06-07-14, 03:54 PM
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Need more insulation...question

My home is a ranch style house, two stories. Its shape is basically a long rectangle. The second story attic is essentially about 100 feet long and 15' wide. The way it was insulated is using batts...they put batting in between the roof joists (with a gap for air movement to the ridge vent) and they put batting in the cieling joist. However, the cieling joist insulation is like R19 and I think the roof rafter insulation is also R19.

Now that its 95 degrees, my AC can't keep up. The AC is sized properly (already checked that) In the room the cieling itself is 82-88 degrees depending on where you are.

My question is, will I benefit from blowing in insulation? I am in the Houston area. All of the can lights are IC rated, and there has been enough work in the attic that some of the batts are out of place....I also already have radiant barrier.

Can I blow in insulation over the existing batting between the ceiling joists? How much can I estimate this to cost?
 
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Old 06-08-14, 10:24 AM
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Just checked my cieling and insulation....cieling insulation is batt and R11. I guess they figured R11 + R19 is R30.....but it doesnt work like that and its still not even minimum code.

I am thinking that its not possible to put 'too much', so since my cieling joists are 2x8, then I can estimate the current R11 is really about R10 or less at 3-4" thick on average. So, if I add an additional 15" of blown in fiberglass, that should take me to R60 on average I think. Did I do that right?
 
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Old 06-08-14, 12:24 PM
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...they put batting in between the roof joists (with a gap for air movement to the ridge vent) and they put batting in the cieling joist. However, the cieling joist insulation is like R19 and I think the roof rafter insulation is also R19.
When you write ceiling (not cieling) joists I assume you mean either rafters or trusses and this is absolutely wrong. If your attic is properly ventilated then you put all the insulation between the ceiling below and the attic space. Adding the insulation to the upper area is only used when the attic is also living space and that requires some different methods of ventilation under the roof deck as well.

Yes, you can blow in additional insulation over that existing on the attic floor PROVIDED you also allow for the free flow of air from the soffit vents to the attic space. I personally would remove any insulation in the overhead.

Others will have more information.
 
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Old 06-09-14, 12:24 PM
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My original plan was to remove that insulation in the roof rafters. However, I believe they did it purely for sound deadening for the metal roof. Is there anything I can do with it beside tear it down? Its a huge waste, and Im not sure if it is actually harming anything since the roof rafter insulation actually stops short of the ridge vent. Here is a picture. It would be nice if I could just leave it. Less work.

http://img.photobucket.com/albums/v1...B4D11CEE8B.jpg

I have looked at this in the past, and the conclusion I, others, and now you have suggested is covered under A and B. Except I am going R60 for 'B'.

Thanks for the advice!

PS: I know how to spell ceiling...I've gotten lazy with the internet. :/
 
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Old 06-15-14, 12:22 PM
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My other question is where do I find Accuvents or some rafter vents that will fit between rafters that are 12" OC.
 
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Old 08-19-14, 07:04 AM
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WRONG THREAD

Disregard this post.
 

Last edited by agdodge4x4; 08-19-14 at 09:50 AM.
 

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