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Old 04-06-2010, 01:50 AM
v7guy v7guy is offline
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Default Insulate between rafters using durovent channels

I raised the ceiling in my garage (consulted an engineer). this meant the joists moved up the rafters. there is approx 4 feet between the hip and the new ceiling height.
I would like to insulate this space since it is essentially an interior "wall" now.
I picked up this durovent styrofoam panel stuff, but it doesn't cover the whole width in between the rafters which has me concerned. I have a vent on each side at each eave, and new vinyl soffits that are perforated so I should have good airflow. Do you guys think the durovents will provide enough of an air path to keep the roof cool and prevent condensation?
I expect to have a heater in there next winter and to keep the temp around 50 give or take. No plans for AC


any experience or thoughts would be appreciated...
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Old 04-06-2010, 02:06 AM
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hello v7guy.

Please check out the first section of our FAQ - the part about posting pictures as attachments. We stopped using embedded images about 4 years ago; the FAQ explains why.

As to the durovents, that sure doesn't look very effective to me.
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Old 04-06-2010, 02:24 AM
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Welcome V7. As cutter said pictures are covered in FAQ. Welcome and feel free to join in.
Be sure to check out these special sections of our site that you might not be aware of:

1. Product/Equipment Review Index

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We look forward to adding your projects, tips or product reviews to these indexes in the near future.
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Old 04-06-2010, 02:45 AM
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Welcome to the site, sorry I cant help.

Doesn't Styrofoam burn like gasoline ?
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Old 04-06-2010, 06:22 AM
v7guy v7guy is offline
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thanks for the welcome guys

Quote:
Originally Posted by GWIZ View Post
Welcome to the site, sorry I cant help.

Doesn't Styrofoam burn like gasoline ?
it melts in gasoline lol

sorry, about the pics, I had skimmed over the rules, but didn't catch that.
whoever changed the pics, thanks for fixing them. I really appreciate it.



I started stapling the panels on and though, hmmmm, that doesn't look right. then I started to search for info, found none. so accordingly I figured I would look here and at the garage journal. GJ has offered no input.

Ideally, I would assume you'd want to cut some rigid plastic or styrofoam to size, space it out for the 1.5-2" space from the sheathing and then insulate over that. but given that contractors commonly use durovent (not that it means much) and that I was only looking to funnel air for 4 ft or so I figured this may be "good enough".

not so?

should I just get some styrofoam and cut to size, silicone on the edges, insulate and then sheetrock over? these panels were .90 a piece, so no biggie.

any thoughts?
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Old 04-06-2010, 07:25 AM
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Those panels are not meant to be the main insulation in a ceiling or a roof, they are designed to provide a path for air to flow into attic space and out of the vents.
Now you need to add fiberglass insulation to the joist bays. Do not try to insulate to full depth as the vent channel will compress the insulation and that will cause it to loose R-value. I looked at the photo's provided and it appears you have 2 X 6 joists, then R-13 or R-19 for 2 X 4 studs will work, then cover the ceiling with 1" thick sheet insulation for added R-value. I had this problem when I remodeled my bed room, I used R-19 on the sloping part of the ceiling with 1" Celotex foam insulation applied over the fiberglass, the flat center section of the room was insulated to R-25 with the 1" of it also. I sealed the seams between the boards with aluminum tape and applied 5/8" drywall over that. The snow does not melt on that section of the roof. I forget what the total R-value of the system is but it works.
Dan.
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Old 04-06-2010, 12:34 PM
kbs2244 kbs2244 is offline
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Default roof insulation

You have the wrong stuff there.
Those are for loose insulation between a flat ceiling joists.

Lots of info here…

Check out the “6 Roofs” first.

http://www.oregon.gov/ENERGY/search....rch.shtml#1068
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Old 04-06-2010, 12:42 PM
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We have an onboard insullation specialist. PM Panhandle Redneck for any questions. Jerry
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Old 04-06-2010, 03:34 PM
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Quote:
Originally Posted by OLD MAN View Post
We have an onboard insullation specialist. PM Panhandle Redneck for any questions. Jerry
Don't call me that!

Quote:
Originally Posted by Lu47Dan View Post
Those panels are not meant to be the main insulation in a ceiling or a roof, they are designed to provide a path for air to flow into attic space and out of the vents.
Now you need to add fiberglass insulation to the joist bays. Do not try to insulate to full depth as the vent channel will compress the insulation and that will cause it to loose R-value. I looked at the photo's provided and it appears you have 2 X 6 joists, then R-13 or R-19 for 2 X 4 studs will work, then cover the ceiling with 1" thick sheet insulation for added R-value. I had this problem when I remodeled my bed room, I used R-19 on the sloping part of the ceiling with 1" Celotex foam insulation applied over the fiberglass, the flat center section of the room was insulated to R-25 with the 1" of it also. I sealed the seams between the boards with aluminum tape and applied 5/8" drywall over that. The snow does not melt on that section of the roof. I forget what the total R-value of the system is but it works.
Dan.
Dan was dead on so no need to say it all again.
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Old 04-06-2010, 06:29 PM
v7guy v7guy is offline
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Thanks guys, so the durovent styrofoam vents will be sufficent for air circulation? I'm reading that right?
I've got some faced R13 in the corner waiting to go up.

Am I also understanding correctly that I should put some rigid foam insulation on top of the rafters like sheetrock and then put sheetrock over that?

Is there a prefered method to fasten the foam to the rafters?
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