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Anonymous
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# Posted: 20 Feb 2013 11:49
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Recently bought a cabin in the aderandaks that has a metal roof over perlins. There is no insulation under the metal or in the rafters. The cabin has sofit and ridge vent the lenght of both sides and roof. Cabin is heated with a wood stove. My plan was to use faced insulation in the rafters (faced towards living area) leaving about an 2" of air space between the metal and insulation. Do I need any vapor barior between the insulation face and the ceiling material? Any suggestions
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bobbotron
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# Posted: 20 Feb 2013 12:13
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Quoting: Anonymous Recently bought a cabin in the aderandaks that has a metal roof over perlins. There is no insulation under the metal or in the rafters. The cabin has sofit and ridge vent the lenght of both sides and roof. Cabin is heated with a wood stove. My plan was to use faced insulation in the rafters (faced towards living area) leaving about an 2" of air space between the metal and insulation. Do I need any vapor barior between the insulation face and the ceiling material? Any suggestions
I think in theory no, as the face provides a vb? In practice, unsure. How deep are the rafters? Have you considered rock wool over fibreglass, if you're going batt insulation? (My choice would be rock wool (roxul))
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Anonymous
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# Posted: 20 Feb 2013 12:28
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Rafters are 2x6 dimensional on 24 center, was going with batt insulation and no haven't looked into the roxul yet.. waiting for the warm weather to start this just want to get all my ducks in a row
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Anonymous
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# Posted: 20 Feb 2013 12:31
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Correction rafters are 2x8 dimensional
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TheCabinCalls
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# Posted: 20 Feb 2013 13:18
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2x8 minus the 2" you want to leave for air space and you aren't left with much at all.
Questions:
- so you have a soffit vent and a ridge vent
- are you trying to insulate between the rafters
- how is the metal roof finished at the facia
- is the inside vaulted or flat? what height is ceiling?
- what size is your room/place
I like to see a picture to see if there are other options.
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Anonymous
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# Posted: 20 Feb 2013 13:38
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1) yes soffit and ridge vent
2)yes trying to insulate between rafters
3) roof ends on both sides with drip edge and fascia is 1x8. The soffit vent is about 5-6" wide and lenght of cabin
4) it is vaulted
5)cabin is 20'x30' with 16'x20' loft and 8'x30' porch
I will see if I have any pics on phone that show it but not sure I do
Thanks
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bobbotron
Member
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# Posted: 20 Feb 2013 15:02
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I read somewhere you could attach a grid of 2x6's (or 2x4's) underneath the existing rafters, so you can put two layers of batts in. Two layers of 2x6" batts is in the R40 range, which is pretty not terrible, if you can spare the lowered head room.
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bobbotron
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# Posted: 21 Feb 2013 09:21
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There's a fine home building article on different options on how to insulate a cathedral ceiling. You can get a 15 day trial period and download it, it will give you different options.
The super fancy option would be to take off the sheet metal, install sheeting, then rigid foam (3 inches or more, approx R15 at 3"), then sheeting, then some kind of WRB, strapping and then the metal roof. Then batts inside the rafter bays. This would go a lot better if you had helpers, as it'd be effort.
Also, whatever you do, don't install pot lights in a cathedral/vaulted ceiling!
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turkeyhunter
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# Posted: 21 Feb 2013 13:42
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place foam DUROVENT (get it Home depot---for cheap $$) between purlings and batts....and no problems from my cabin done this way...
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Anonymous
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# Posted: 21 Feb 2013 16:58
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Thanks for all the adivice. Would love to take roof off and do it right way but cabin is only 9 months old so dont feel like taring the roof off. Not so concerned with the r rating as my wood stove is oversized and also have a propane wall heater. Like the durovent idea. Saw it at home depot when pricing insulation looks easy to install and would leave pleanty of air space for my ridge and soffit vent
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