I need to frame a curved ceiling in my bedroom. (see attached) It will peak about 3″ above the transom window and curve down to the two orange dots on the 2×12 header over the triple windows (that point is 8′ from the floor). From there, an 8′ flat ceiling will continue horizontally until it hits the 12 pitch ceiling joists, at which time I’ll follow the 12 pitch down to the knee wall. Everything will be drywalled (not by me!!).
I have some ideas about how I would frame it, but I’d like to leave it as a blank slate and see what people come up with. Keep in mind I’m just a DIY guy so I don’t have to make money at this game. I also have a bandsaw so I can quickly cut a curve for the joists if that is part of the plan.
The chord length is ~108″ and the height from the chord is 28.5″, giving me about a 5.5′ radius. The span from the front wall (in the picture) to the back wall of the bedroom (where I’m standing to take the picture) is about 13′ (I assume this is important because there will probably need to be some kind of header where the roof goes from curved to flat (at the orange dots)).
Hope this all makes sense, let me know if I left something out or you need more pictures.
I’ve never curved drywall before so I don’t know what kind of framing member spacing is required for this curve. I’ve read a little bit, but would like to here from some people in reality.
MERC
Edited 6/1/2005 6:10 pm ET by DJ Merc
Edited 6/1/2005 6:11 pm ET by DJ Merc
Replies
I'm not a math wizard. To begin with I snap a line on the floor tic off two marks 108'' 's apart. Then I strike a perpendicular bisector. I measure up the perpendicular line 28.5'' 's and then connect that point to either one of the original points, and then snap this line. Make a perpendicular bisector to this line also. Measuring from where the two bisectors converge to the point 28.5 inches up from the first perpendicular line gives me the length of my radius. If the bearing is good on the back wall, where you took the picture from and the wall with the window in it, headers are probably the easiest route. Install the header with hangers on the widow wall. Now we have a header from both orange dots back to where you were standing when you took the picture. Now strike the radius on some 3/4 ply and cut it out and glue and screw together a laminated radius that will serve as both structure and pattern. I would cut the span down to about 3' 6'' meaning I would make three of the doubles (radius ply patterns) and two single thick one to apply directly to the front and back wall. Before putting them up lay them out for 2x4 or 2x6 framed in between around the circumference on roughly 8'' center. Cut a notch for them to set up on the header. Then install sliding them up onto the headers and lift it up and nail it to the face of the rafters. One closest to 3' 6'', next closest to 7' and so on. The I toenail in my framing. I think that gives me a barrel vault. Ask the DW man how to hang it.
Edited 6/1/2005 9:40 pm ET by quicksilver
I appreciate the response. I like only making a few curved members and then building a 2x4 ladder between them.
How do you handle the 108" span with plywood? I guess I could build up enough layers that I could have a splice.
My approach was to use 2x8 or 2x10 segments 32" long. They would be mitered at each end (18 degrees by my computations) and joined end to end using big biscuits (4 of them I guess) (before anybody gets worked up about biscuits, try cutting a 2x4 in half and rejoining it with a couple of biscuits - you'll never get those biscuits to break). That would make me a segmented arch, which I could then trace my curve on and run through the bandsaw to produces the ceiling arch. Using 32" segments with a 5'6" radius gives me about a 2" "cut-in", so my 2x8's would become 2x6 at the smallest point.
What size header is required to span 13" carrying only ceiling load? double 2x10, double 2x12?
MERC.
I think 2x10 or 12 would be ok for the header. Use 2x12 unless it creates some difficulty. I think if you tie your ply form to the rafters and take off some load it letting it work in tension everything should work nicely.