Thinking about going to a raised cathedral ceiling, but need advice

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Old 10-03-14, 09:54 AM
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Thinking about going to a raised cathedral ceiling, but need advice

Hi Guys,

I've been doing some research on a remodel I'm working on. I have a room that's about 80 sq feet that was an extension on the back of my house. Right now, this is what the room looks like.



Since the room is somewhat small, I'm considering pulling the ceiling joists to make a cathedral ceiling. The joists are about 10' wide, so I'm guessing the rafters are probably around 7' long. They are 2 x 6's spaced at 24" vertical. The worst snow we've had here I think has been like 20" (I'm in Huntersville, NC right at the NC/SC border), and that was like the worst storm in 50 years.

If I removed the joists, would I have to worry about the roof being supported? It is an asphalt shingle roof that extends about 8' from the house. Also, I was just going to insert some insulation with the paper on it between the roof decking, the rafters, and then secure drywall directly to the rafters. Would that be the best way to make the cathedral ceiling? Thanks for any advice guys
 
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Old 10-03-14, 10:21 AM
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Yes, you do have structural concerns. The ceiling joists are doing more than just holding up the sheetrock and insulation. They are tying the walls together. Because of the angle of the roof rafters their load is pushing outward and the ceiling joist forms a triangle (a good structural shape) and prevents the bottom of the rafter and top of the walls from being pushed out. Vaulted ceilings are commonly done though. You might be able to do collar or rafter ties but I think you'll also have to go to taller rafters to have enough room for insulation.
 
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Old 10-03-14, 11:17 AM
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I'm trying to picture why a room so small would have a ridged roof.

I would guess the ceiling joists pictured above are running parallel to the back wall of the house.

IMO: To properly construct a vaulted ceiling, roofing material/sheathing and rafters/joists would need removed. You would install scissor trusses and replace roofing. Sounds like a lot of work, but my only concern would be matching shingles and ensuring a water tight roof after tying it back in.
 
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Old 10-03-14, 11:18 AM
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Yes, there are ways to convert that room to a cathedral ceiling, but not as you have suggested, as Pilot explained.

Happy to go into detains if you are prepared for a somewhat major project.

Supporting the ridge beam and then sistering some custom made scissor trusses to each rafter is one way. Insulation and ventilation would need to be addressed.

From the looks of the sheathing up there and the insulation around the electrical box, the current air sealing, ventilation, and insulation needs to be fixed anyway.

Bud
Sorry if I repeated. You're too fast for me Handyone
 

Last edited by Bud9051; 10-03-14 at 11:20 AM. Reason: slow
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Old 10-03-14, 11:23 AM
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sistering some custom made scissor trusses to each rafter
That's even better. Good job Bud.
 
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Old 10-04-14, 05:42 AM
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It sounds like foregoing the cathedral ceiling is the way to go on this particular projection.

Bud, you mentioned issues with the way the structure is presently (sheathing, electrical box, insulation, etc). What improvements should I plan on making?

Thanks for all the great advice guys. It's pretty obvious the previous home owner did most of this work, and didn't have a clue what they were doing and did a crappy job.

I'm a noob at this stuff, so I appreciate all the great direction. I'm kind of 'dipping my toe in the water' when it comes to this remodeling stuff to see if it's something I enjoy doing (since I'm currently a stay at home dad ...aka... unemployed).

Time to get back to the roofing issues so I can move on and tackle these issues.

Thanks again guys
 
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Old 10-04-14, 06:25 AM
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There is another approach to give you the feeling of more height. Leave the current joists in place and install the scissor joists above them where you will attach your new drywall. You can treat the open beams as you wish, cleaned up with stain and/or varnish or simply paint them. At 24" on center there will only be a few joists left exposed.

As for what I can see from the picture, the sheathing looks like it has a moisture problem, aka mold. I see no ridge vent so I'll ask if there is a gable vent or other high vent combined with soffit venting or other low vents? The dirty pink fiberglass insulation around the electrical box is an indication of air leakage. The fiberglass lets the air pass and filters out all of the dust. When the new drywall is installed it should be treated as the air barrier. Whether a vapor barrier is ultimately needed is TBD.

To get more specific I will need more pictures and answers to the ventilation questions.
Also, is this space heated and air conditioned?

Here are a bunch of photos of scissor truss applications.
Scissor Truss Design Ideas, Pictures, Remodel and Decor

Bud
 
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Old 10-04-14, 07:30 AM
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The existing roof, rafters and joists don't all need to be totally replaced, necessarily. If you get a structural engineer involved, he can tell you how to configure the existing rafters to create your vaulted ceiling. To do this, you would not remove ALL the ceiling joists at the same time, you would either modify them one by one, or perhaps every other one, until you have modified the entire structure.

The modifications would likely involve a cross tie between rafters, at the desired ceiling height. The center point of the cross tie would have either two vertical members or two diagonal supports that are attached to the rafters near the ridge beam. Then your new ceiling joists would attach to the center point of the cross tie. All this would probably need to be bolted together with 1/2" bolts.

This isn't something you should attempt yourself without having a structural engineers plans and approval, since they are the ones who have the software to run the calculations on snowload and other forces.
 
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