Attic insulation install, r value needed?

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  #1  
Old 02-21-17, 07:09 PM
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Attic insulation install, r value needed?

We're renovating a room that is essentially an attic. Stripped it down and are now ready to insulate. We are using the Roxul insulation, R30. I live in CT and the recommended r value is 49-60 which means we would need two layers of the 30. I've put in one package of batts and they are going perpendicular to the rafter ties. The next layer will go in parallel. What I am wondering though is this. After installing the next layer and pushing up the first, it will leave only about a foot to the peak of the roof (which has a ridge vent it's entire length). Is this an issue? Also, the gables will mean when I push up the top layer from underneath, it will compress against the rafter in those spots. Will this be an issue? I've included some photos to show what I'm talking about. Should we just install the insulation one layer deep parallel with the rafter ties and call it a day at R30? Since it's open now I'd rather spend the money upfront and save on the heating/cooling but I just don't know if there will be issues with pinching and how much space is left.

Apparently the images uploaded sideways for whatever reason and I can't fix it. So you'll have to **** your head to the left to see them the right way.
 
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Old 02-21-17, 07:36 PM
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Is there any ventilation besides the ridge vent, such as soffit vents or gable vents?
 
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Old 02-21-17, 09:21 PM
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You aren't going to get much insulation in those rafters below the ceiling (2x8?), so IMO it doesn't make much sense to go bananas (R60) on the ceiling when the side rafters will only have 8". And if you are saying you are going to put insulation between your ceiling joists next, (insulating from below) use insulation for a 2x6 so that it doesn't push the other insulation up at all. First, get those perpendicular batts tight together so there are no gaps between them.
 
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Old 02-22-17, 03:57 AM
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There's plenty of ventilation with gable vents and soffits. I will be using vent's behind the insulation along the gabled part of the walls to keep from blocking airflow from the soffit to the ridge.

The rafter ties are 2x4 so anything other than the roxul wall insulation(meant for 2x4 and only R15) will push the batts above it up closer to the ridge. The rafters themselves are 2x6. Yes when I'm buttoning everything up there won't be any gaps in the insulation.
 
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