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Montanagirl
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# Posted: 5 Dec 2012 01:57pm
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My 80 year old cabin has a metal roof over a composite roof. Currently it has a drop ceiling with insulation layed over the top of that. (the nasty pink rolled stuff from the mid 70's). I would love to pull out the drop ceiling to add visiual height but would like to retain some insulation up there maybe with T&G. I've heard about having to be careful to allow for ventilation . . . not sure how to proceed. . . I thought I read something similar on this site, but couldn't find the thread.
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GomerPile
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# Posted: 5 Dec 2012 02:19pm
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You first need to see how the roof is constructed (2x6, 2x8, 2x10). In other word how many inched of insulation will you be able to stuff in the roof joists? I bet your nasty pink insulation is probably giving you a substantial amount of insulation value.
Looking at this page and determine how much insulation you should have: http://www.homeconstructionimprovement.com/recommended-insulation-levels/
Armed with more info you will get better suggestions...
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Montanagirl
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# Posted: 5 Dec 2012 03:04pm
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Thanks GP! Yeh, my brother is happy with the way things are . . . you know us girls, we want things to look nicer (even tho, it's more functional the way it is!) LOL . . . I'll see what I can find as far as joists go . . .
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Malamute
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# Posted: 5 Dec 2012 04:56pm
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The roof may be boards laid vertically over the purlins, no rafters. If so, you can use foam board insualtion between the purlins, then face with T&G set between the purlins, The foam board will be a vapor barrier, and wouldnt soak up condensation like fiberglass does if it gets condensation in it. You could also take the outside roof off, lay 2xwhatever on edge, insulate with foam board,or fiberglass, then resheath with sheet stock (OSB or plywood) then re-roof. The last is essentually how I build cabin roofs, but doing it from the beginning is simpler than retro-fitting insulation and rafters over the top.
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TheCabinCalls
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# Posted: 6 Dec 2012 10:04am
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- are you trying to vault the ceiling or just update the look
- are there any utilities running in the space above the drop ceiling?
- how is the roof constructed
- what else is above the drop ceiling?
- how much height are you able to gain?
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Montanagirl
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# Posted: 6 Dec 2012 04:16pm
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Just trying to update the look. The only utilities are wiring that could easily be rerouted if necessary. I'd say the height is about 5.5 feet from the false ceiling to the tallest point of the roof. The only thing above the drop ceiling is the insulation and the rafters. I don't have an interior photo, but you can see from this picture the rafters run from front to back. Disregard the covered porch, I'm thinking of the main body of the cabin.
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TheCabinCalls
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# Posted: 7 Dec 2012 08:30am
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So they are rafters for sure. I see snow so you want at least an R38 for full year usage. So if the cavity of your rafters are 9" or bigger you might be able to go fiberglass batts only. If they are 9" or smaller you might need to: 1. add new boards to make the depth more or 2. go hybird rigid foam and batts. So if you had 2x8"s you could go R24 or R30 in the between rafters and put a couple inches of rigid foam attached to the rafters and put drywall or t&g ceiling on that (with long screws of course).
Now to venting...
Was the drop ceiling added later or was it meant to be the ceiling? Meaning is the roof vented and is that entire 5.5 ft area open like an attic? If so that area is roughly the same temp as it is outside so that the roof can last longer. Which also means that along with stuffing the rafters with insulation you have to have a air channels from soffit to ridge vent.
Now if you have the money or know how you can rip everything out and use spray foam. If closed cell you wouldn't need to vent and you'd get your R value. My guess is that would be around $1500.
Now cosmetic...
If you take out the drop ceiling your are going to be left with more than just insulation and electric to tackle. You will have ceiling and two gable ends to refinish. You have probably thought about the ceiling since that is the reason you started this thread. However, have you thought about the gable walls. Will it need to be done in the same material as the walls. Will you have interior walls that will need to be extended? Will they need to be insulated as well? They could get a different treatment like you have on the outside and that would look nice.
Loft option...
- 5.5 ft area: could that be used as a sleep loft? thinking about the bedroom/bathroom. Keep their interwalls the same and make a loft above.
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Montanagirl
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# Posted: 7 Dec 2012 09:19am - Edited by: Montanagirl
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Wow, thanks for the indepth advice!!!! Just what I was looking for! I suspected it would not be as easy as I hoped) LOL . . . The ceiling was added later and yes it is just a large open space. I don't think the ceiling is vented. It is just a seasonal cabin, we are not up there in the winter. Although if we got some insulation under the floors that might be an option! but that is a different project. LOL . . . I had thought about the exposed rafters and what they would look like. ( I remember as a little girl sometimes we'd see a mouse run along them as I laid in bed! (Probably why my mom wanted the ceiling LOL) Fortunately we got all holes buttoned up and have not had a mouse problem since). Good point on the interior walls. Currently they are painted wood paneling (with insulation) not sure if they will need to be extened . . . mmmmmm lots to think about. 
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Montanagirl
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# Posted: 7 Dec 2012 10:39am - Edited by: Montanagirl
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I pulled this photo from a magazine article. They had removed the drop ceiling. It appears tho, they do not have rafters nor did they insulate. But you get the idea of how much bigger the room seems
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Malamute
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# Posted: 7 Dec 2012 07:11pm
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It makes sense after seeing the pictures.
Another insulation option is blown in, the depth of the ceiling joists doesnt matter with blown in insulation. You could also vent the gable ends, rather than the eaves, tho both would be good.
If you wanted to remove the ceiling, you could add on to the rafters to give more insulation space, or just cover with tongue and groove boards over the rafters. As cabin calls said, you'd need to provide an air space between the insulation and roof sheathing. The C (cathedral) type insualtion gives the stated R value, but is slightly shorter and gives an air space for ventilation. You'd need to provide a vent along the ridge, and at the eaves.
You could also do a faux scissor truss type arrangment. It gives more insulation and vent space, but still opens up the room.
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Montanagirl
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# Posted: 8 Dec 2012 10:58pm
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again, many thanks! how hard is it to ad a ridge vent after the fact? I'm thinking I'm talking myself out of this . . .
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Montanagirl
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# Posted: 8 Dec 2012 11:16pm - Edited by: Montanagirl
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here's another photo that gave me this idea. Granted I won't be painting things white, and but they have exposed rafters.
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Malamute
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# Posted: 9 Dec 2012 12:20am
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It isn't that tough to add a ridge vent, tho if you raise the ceiling, it adds a fair bit of space you have to heat before you feel it down at living space level. Some like fans to move the warm air down to you, but,...you still have a larger volume of space to heat, and, to me, moving air feels cool. I'd rather not have a fan going in the winter, just have warm air around me that isn't moving.
It could possibly feel cooler in the summer wth a higher ceiling, but with the current ceiling insulated, it may not help, and could be going backwards in feeling cool in the summer.
I agree about it feeling larger with higher ceilings. Everything comes with a trade off though.
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Montanagirl
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# Posted: 9 Dec 2012 12:42am
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Yeh, the beauty of living in NW Montana is we don't worry about cooling . . . even in summer . . . LOL . . I'm sure that's why my grandpa, dad, and brother labored to put in the drop ceiling . . .cleaner (no mouse droppings or spiders dropping from the rafters), warmer, more efficient (cheaper electric bill and less wood to chop) . . . I'm cursed with wanting things to look roomier LOL . . . guess I need to turn off the HGTV . . . LOL . . .
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