# Insulation in vaulted ceiling help please!!!!



## pri6175 (Jan 21, 2012)

Ok so we built a 2 room addition on my parents trailer and I need some advice from you knowledgeable people out there and I need it bad! I will put pictures up so you guys know what Im talking about. Heres the situation.

I have a 15ft x 30ft addition connected to a trailer with 1ft. overhang all the way around. The framing is all done and we are trying to start insulating. The Ceilings are where all my questions are. I have a 10ft. ridge vent installed in the center of the roof. We will have vaulted ceilings so I installed some of the rafter vents. I ran them all the way up from eaves to ridge vent. My 1st question/problem 

#1. what do I do between the rafters that have no ridge vent at the top? do i run vents up through there anyway? I was thinking if I did that then the moisture would just get trapped in there. So I came here because I don't want to do it wrong. Do I just close those up? then there would only be ventilation between the 8 center rafters. see rafter vents.jpg That would mean that I have 2 rafters on each outer end without vents and the 8 in the middle have vents that run all the way up to the ridge vent.

#2. I have spray foamed around the eaves where the rafter vents meet the eaves so should I do that or leave it open around the rafter vents? #3. same as the previous question except at the ridge vents...not sure if i should foam around the vents or leave them open for the air to travel through there.... see rafter vent closeup.jpg

I have only done between 5 rafters on each side so far. 
I guess this is a good place to start with getting some info. I have other questions that I will post as this thread develops. Any info. you guys can provide me would be great and I would really appreciate the advice. I just do not want to do it wrong and have to do it all over again. Im trying to avoid mold and trying to keep it warm in there. I will attach photos so u can see what Im talking about.


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## pri6175 (Jan 21, 2012)

btw I we r located in western PA. we used unfaced insualtion under the floor and poly over top the insulation and plan to do the same on the ceiling. thanks again for any advice you can offer....I can't stop thinking about how to do this right....


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## titanoman (Nov 27, 2011)

Extend the vents accordingly?


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## joecaption (Nov 30, 2011)

You now have the vaper barrier on the wrong side under the house.
It should have been faced insulation with it facing the subfloor.
Now the moisture from the room will be traped.
Did you install a vaper barrier on the ground under the addition?


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## titanoman (Nov 27, 2011)

joecaption said:


> You now have the vaper barrier on the wrong side under the house.
> It should have been faced insulation with it facing the subfloor.
> Now the moisture from the room will be traped.
> Did you install a vaper barrier on the ground under the addition?


You must be seeing something I'm not. Are there pictures of the floor there?


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## Gary in WA (Mar 11, 2009)

The ridge vent has to vent every bay. The OSB sheathing is installed wrong side up, maybe not.... The rafters are under-sized due to being seat-cut ripped incorrectly; pp. 38: http://books.google.com/books?id=iwSasc7rowcC&pg=PA38&lpg=PA38&dq=heel+or+toe+bearing+with+rafter&source=bl&ots=QXpuP2csh6&sig=aBxUyKfe4mv2pWTq5bQon4cZvj8&hl=en&ei=L8gnTIqtL9CHnQfkk9m8Bg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBIQ6AEwAA#v=onepage&q=heel%20or%20toe%20bearing%20with%20rafter&f=false
You need continuous soffit venting. The f.g. wall insulation install is poor leading to convective loops; http://oikos.com/library/insulating_framed_walls/index.html
Gaps between drywall/insulation of 1/32" or more degrade f.g.: http://www.advancedinsulationinc.com/resources/Getting_Quality_from_Fiberglass_Insulation.pdf
Biggest problem is the missing rafter material that requires a hanger not to split from bearing point upward. You essentially now have 2x4 rafters = PA, western= Zone 5; http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_11_sec001_par001.htm *2x4 span= 8'2" @ 16"o.c. or 6'8" @ 24"o.c.* ; http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_8_sec002_par023.htm

R-13 in wall, R-5 foamboard on exterior side, *R-38 required in ceiling*, R-30 in floor: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_11_sec002.htm
Sorry to be the bearer of bad news...

Gary


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## joecaption (Nov 30, 2011)

No picture, the OP said it in his first post.

There's spray foam stoping the air flow into the foam baffles from the soffits.
If those are just 2 X 6's rafters there's no way to fit the mim. R-30 insulation in the bay. At the lower end you would have to use R13 to even fit it in the bay which may cause ice dams from that area being warmer.
There's no way now to lay sheetrock flat on the ceiling due to the rafters being cut wrong.


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## titanoman (Nov 27, 2011)

Oh. I'm sorry. It's in his second post, that I didn't see. My bad...


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## titanoman (Nov 27, 2011)

They are some FINE looking rafters!
I like the big header on the wall too,
or maybe it's a ridge beam on a wall.


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## pri6175 (Jan 21, 2012)

*Thanks for the quick response!*

Thanks for all the replys. Well, I am concerned with some of the responses.

joecaption - There is no vapor barrier on the ground under the addition. Im not sure if the insulation is faced or not. I assumed it wasn't. I do know this.
It is R-30 between 2x12's 16" spacing and covered with 6mil poly. I will have to check to see if the insulation is faced. If it is, it is facing the subfloor.
The foam is not stopping the air flow from getting into the baffles, I just sprayed around them at both the eaves and ridge vent. I am trying to figure out what to do about not being able to put R30 in the ceiling. Not 

"There's no way now to lay sheetrock flat on the ceiling due to the rafters being cut wrong. " - Not worried about that as I can make it work pretty easily. My concerns are doing the ceiling properly. Thank you for pointing out about needing faced insulation under the floor though, i will check that tom. I thought I read not to use both poly and faced insulation together.

*GBR in WA* - You say The ridge vent has to vent every bay but I read that running a ridge vent the whole way accross would cause over exhaust? So what would you recommend I do? Run a ridge vent the whole span across the roof?
I know the rafters are undersized. Thats why we had to build 2 walls because the span on a 2x6 can't be more than 11' 3".
I too, didnt like the idea of not being able to use r-30 in the ceiling but what can I do? Should I attach 2x10's to the rafters and use joist hangers and then I can use R-30 also? Should I be using foam around the baffles to stop all other air flow in each bay? I foamed about 5 of the bays at the eaves and ridge vent around the baffles. Is it wrong to leave them unfoamed? 
We used R-19 in the walls but there is no foam board on the exterior.
What do you see in the wall insulation that is poor? the areas around the wiring? I was thinking I should cut the insulation so that I can put it around the wiring so that it is not compressed as much.
Thanks for the help. I really appreciate it!

titanoman - Nice to see you are getting a good laugh, It seems to me the guys who did the framing started skimping on the materials when they got to the roof. they used 2x12's on the bottom but cut down 2x6's on the ceiling. I am not very happy about this at all but we already paid them so I doubt we could do anything about this now, our contract is very vague, and we really do not have the money to take legal action. We just want to try and finish this the best possible way. Any useful advice would be appreciated though....

I am trying to decide the best action to take next. Any help is appreciated.


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## Gary in WA (Mar 11, 2009)

"You say The ridge vent has to vent every bay but I read that running a ridge vent the whole way accross would cause over exhaust? So what would you recommend I do? Run a ridge vent the whole span across the roof?
I know the rafters are undersized. Thats why we had to build 2 walls because the span on a 2x6 can't be more than 11' 3".
I too, didnt like the idea of not being able to use r-30 in the ceiling but what can I do? Should I attach 2x10's to the rafters and use joist hangers and then I can use R-30 also? Should I be using foam around the baffles to stop all other air flow in each bay? I foamed about 5 of the bays at the eaves and ridge vent around the baffles. Is it wrong to leave them unfoamed? 
We used R-19 in the walls but there is no foam board on the exterior.
What do you see in the wall insulation that is poor? the areas around the wiring? I was thinking I should cut the insulation so that I can put it around the wiring so that it is not compressed as much."-------

The ridge vent should vent all cavities, same NFVA as the soffit vents: http://www.buildingscience.com/documents/published-articles/pa-crash-course-in-roof-venting Yes, whole span.

Attach 2x's to the rafter bottoms to get required R-value, also use special "cathedral ceiling" (R-38) insulation for minimal headroom loss.
Work with local AHJ on the rafter fix as they will have final say. Check on local wall insulation requirements while there, getting the permit to finish this. Baffles in article sited above.
Wiring insulation: http://www.buildingscience.com/documents/information-sheets/installation-of-cavity-insulation/
Paper vapor retarder (Class 2) is fine on the floor, walls and roof, I would not use poly;http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_6_sec001_par003.htm

Zone 5: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_6_sec001_par005.htm
If already on the bottom of the floor sheathing, leave it, but no other, as Joe said.

Gary


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