Multiple Questions About Finishing an Attic

Old 01-30-04, 02:27 PM
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Multiple Questions About Finishing an Attic

I am finishing off my attic myself (mostly) and have several questions. I hope someone can help.

I have an A frame roof line in my attic. The room is about 15x30 feet from knee wall to knee wall with some storage behind some of the walls and some duct work, heat pump and blown insulation behind other parts.
I have a vented ridge cap at the top of the roof for ventilation.

1. Someone suggested that I put a fan with a thermoustat behind my knee walls. The purpose is to keep the air from being stagnant and moisture develping which after several years may develop into a problem. Does this sound necessary?
The winters where I live have normal lows in the 20-30s. The Summers have highs in the 80-90s.

2. I'm going to put insulation on the roofline between the plywood roof and the drywall ceiling. Do I need to have something else between the insulation and the plywood roof to let air in between? Someone suggested that I put something that's sort of like an egg crate design to let air flow?

3. Is there anything else I should do for ventilation?

4. What type (r factor) do I need to put at the roof line? Should it be paper backed with the paper toward the drywall? Should the paper be stapled to both sides of the rafters so that it's flush with the rafters? Do I need a special insulation near my chimney or duct work? What happens if I press the insulation right next to the plywood roof? Do I need a vapor barier placed between the insulation and the drywall?

5. I plan to have recessed lights in the ceiling. Does the insulation need to be kept away from the light fixture?

6. How far do the recessed lights need to be kept away from any wood or anything else that might be above the drywall ceiling?

I know that I've asked a lot of questions, but I'm hoping for some help.

Please advise.

Thanks, in advance, for your assistance!
Old 01-30-04, 04:41 PM
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Non-expert homeowner first line of defense here.

For #2, there are baffles that can be put between the insulation and roof decking to allow air flow from the eaves to the ridge, I think some are made of styrofoam. If you've got enough soffit venting, this should take care of the need for any fan described in #1.
Old 01-31-04, 05:18 PM
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I had a very similar situation. Where I am, the city requires a 3" air space between the insulation and the underneath side of the roof decking. I nailed furring strips to each side of the rafter and then stapled (1/4" crown) 1/4" OSB to that. This didn't leave much for insulation, so I attached another 2"x6" to the rafter. I drilled 3/8" holes every 8" about 4'1/2" deep and used 3" drywall screws (using a long-shanked bit on my drill/driver). I had to allow for this in placing my knee-wall so that it would still be 5'. Incidently, we use the styrofoam product you mentioned, but it is only allowed where the roof passes over an exterior wall, to keep insulation from blocking air passage. Every place where a rafter is also used for the ceiling in the room below (as in cathedral ceilings) the inspector require the 3" space mentioned above.
Old 04-04-04, 12:35 PM
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Thanks for your help.
I have resolved the issue with the fan behind the knee walls and I have started to install the rafter baffles to help ventilate the roof by keeping the insulation away from part of the roof boards.

I still have a couple of questions left, I will post a new question(s) for these.

Thanks again!

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