Greetings all!
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I’m venturing over from the woodworking forums because I have a few questions about a project. I’ve just started to redo my girlfriends attic area and I want to put in a partial barrel ceiling. The roof pitch is 17/12 and rather than just hanging drywall up to the inside peak, I want to have about a 1.5’-2’ radius at the peak. I’m planning on building a couple of forms to shape the radius of my drywall but how should I bent it? Length wise or with wise? And how should I frame my radius at the roof peak? I’ve thought about building frames out of plywood or is there a special type of bending board for this type of application? I’m also curious about what to do with my ceiling rafters. I have ceiling rafters about 7’ high every 24†and plan to remove every other one and raise them 2’ and then box them making them into beams. Can I remove all the rafters, install my drywall, then attach like a 2 x 2 4 inches long to the roof rafter over the drywall to attach my box beam or is there some type of hardware I need to use? I’m trying to not have to drywall with my beams in place.
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Any and all advice is welcome.
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Thanks
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IMSA
Replies
Two opinions.
First, what you are calling ceiling rafters are collar ties. These may or may not have an important structural function. If they are important structurally, you should not take them out or move them without understanding this function. A competent carpenter should be able to figure this out roughly or an engineer precisely.
Second, I don't think you will be able to bend drywall into that tight a radius. Plaster would probably be your best bet, though it will take a bit of practice and research to be able to do what you want. Once you know how to do it, it won't take that much time. Of course it may take weeks before you know how to do it.
Good luck.
Ditto on the tight radius. Check the drywall mfg. for the radius specs on their 1/4" product. You can also gain additional flexibility by first wetting both sides of a DW sheet, letting this film soak in for 30min or so, then applying. This I have not done, but have seen it done by a kick azz crew.
If you have to go the plaster route, it will probably be useful to tightly staple some expanded metal lath onto your substrate. Pool trowel would help too.
the collar ties should be doing nothing... this has been discussed 1000x... if the floor joists you are standing on while looking at the collar ties are running in the same direction... all your tie'n together is already done... chances are they are way up the rafters and at that point they are about useless anyway...
I've seen some tight radius situations like you want framed with 3/4 plywood cut to the desired radius and nailed to your rafters aprox every 8ft where they (the plywood) fit up alongside the rafters (kinda where your collar ties were) place/position one at each end of your desired arched ceiling... lets assume this is 16ft long end to end... then you'd place a 3rd plywood gusset/formboard whatever... in or close to the center (using stringlines beween your first 2 plywood form/gussets to position the center one or ones in plane with the first 2)... wherever the closest rafter is that you can nail it to... then using 2x4's frame between the plywood letting the 1 1/2" edge of the 2x follow the plywood form... place them about 6-7" on center... the more 2x's the better so that you can follow the radius closely and have a a tight nailing surface for your drywall...
hope that wasn't too screwed up for you to follow... i have seen guys first cover something like this in cheap 1/4" luan plywood... before the drywall...
good luck
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Thanks everyone for the advice. While we're at it I have another question. Since it's an older home, the roof rafters are 2 x 4. would I be smart to fir out the 2 x 4"s with 2 x 2's to create basically a 2 x 6's for added insulation?
Thanks
IMSA
Extra insulation is good but you'll probably want to go more than just a 6" depth on the fir-out of your rafters to gain the r-value that you'll need as well as an air gap between the roof deck and the insulation. To get R-33 you'll have to sister on 2x10s or bigger to the existing 2x4 rafters.
Since it's an older home, the roof rafters are 2 x 4. would I be smart to fir out the 2 x 4"s with 2 x 2's to create basically a 2 x 6's for added insulation
Many other question in there.
First off, we probably ought to address the span issue. How far will the rafters have to stretch after this change? Could be you may need 2x8 or 2x10 to carry the roof loads (especially after removing any rafter or collar ties).
Next, the insulation ought to be part of the planning up front, not something at the end. If you are going to have a ventilated roof behind the knee walls (and the rest of the attic that is not this room), then that ventilation has to be carried up over this new room (or some provision made for proper ventilation).
Ok, collar/rafter ties are one can of worms, ventilated roofs are another. C'est la vie <sigh>.
Might help the structural side of things to get "us" some photos and/or sketches.
Now, as to coving drywall--that's mostly down to your patience and your hand with mud. Just about any radius can be made, the trick is how much effort it takes to make that radius. Rip your d/w sheets to 4" wide, and they'll go into the space a little bit easier. Lapping 1/4" thick sheets can help that.
Now, that'll leave gaps & joints. They will want filling. You have to go slow at that. A bit like taking a square timber to round by planing it to octagonal, then 16-sided, and reducint the facets until it's all round. Making a "knife" from sheet metal to match your desired finished radius can help too.
All that being said, you may have a bit more comfort lever with a larger radius.Occupational hazard of my occupation not being around (sorry Bubba)
I'll take a couple of pictures later and I'm sure that will help a lot in explaining what I'm trying to do.
IMSA
do plaster...you'll love it
Agreed, plaster is the way to go, it's too tight a radius by my calculations. If you have never plastered before, then find someone who knows how and have them do it or help.