Framing Cathedral Ceiling - Options

Thompsy

Hello,

I am doing an addition for customer that is a 24'x22' extension of a gable end of the house.. The addition will be roughly 6/12 roof pitch.

The customer wants a cathedral ceiling. I am deciding between using Scissor trusses OR using rafters and a ridge girder(beam).

I am going to place some windows in the gable end so I am thinking using rafters would give me more room to (and also create a higher ceiling)

Does anyone with experience doing this know appox. what size ridge beam to use? In this situation? It is also upsate NY so snow is plentiful.

Also with having a window under a ridge beam, can I just make header to support the ridge beam to transfer the load to the foundation? (like above a door in a bearing wall)

any tips or links to sites would be great!
Thanks

Dan_Watson

Hi.

genecarp

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woodworkbykirk

more than likely youll need to get an engineer to spec that

mikec

What does it show on the print? I'm sure you must have one that has been approved by the building dept, right?

Thompsy

Nope, just planning stages at this point..

CrpntrFrk

The customer wants a cathedral ceiling.


Not sure what this is! Is it an arched ceiling or groin arched ceiling?

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surf6524

I did that design on my own home about 6yrs ago. It was the master bedroom approx 16'x24', with a 8' circle top window at the gable end. I also had a choice of using scissor trusses or an engineered ridge beam. I chose the engineered beam for the same reasons your contemplating, to get a higher pitch. The main ridge beam had one end supported by another smaller parallam beam which acted as the header over the window. The opposite end had a triple 2x4 which carried the load down to a squash block in between the floor joists, then the same triple 2by/squash block down to the first floor and finally a lally column in the basement. I clipped the ceiling slightly so the hvac contractor could run his trunk line down the length for his feeds. All the enginnering for the beams were done at my lumber yard by TrusJoist. Skylights were also added, and I liked the fact that I didn't have to build tunnels through trusses. I have a full 8/12 pitch, not the 6/12 if I used trusses. It's more work this may, but I think the end result is a lot better.

NorthstarNC

Thompsy

Hahha nice picture.. What do you like for attaching the rafter to the ridge beam?

TimelessQuality

nails and gravity....

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Thompsy

Yup when I build with rafters and have ceiling joists, I just nail. But with the absence of joists do you think I should use metal connector?
Either that or I was thinking of making the rafters go over the ridge beam and nail them samwiched together on top...

surf6524

You can use rafter hangers on the beam, but on the run you have, it can get pretty expensive real quick. Their really not necessary. One way is to have the rafters butt each other, then toe nail them to the beam, and to each other, then nail a plywood gusset to one side. Another way even easier is just what you said, run them next to each other, let them overhang, nail them together,(5 or 6 10d's), then cut off the waste. Faster than hangers, and a lot less money too. Make sure your notch doesn't go more than 1/4 the depth of the rafter stock. Good luck on your project.

Gus Dering

don't forget a venting detail at the top.
In earthquake country that can be a little trickier than western NY but you still need to vent each one of those bays

Aframe

Depending on the detail you are looking for at the ceiling peak, and how wide the ridge beam is will guide you for the best location (below rafter or in line like a normal ridge board.)

You may end up with a flat spot under the beam even if you set it up in line with the rafters, again depends on beam and rafter sizes. If you go with an inline ridge beam you can set the beam a bit lower than the top of the rafters for venting, and so you don't end up with a large flat area on top run the sheathing up past the top of rafters an inch or so.

You will need to use metal connectors at the rafter/plate connection. You won't need hangers at the top (unless the engineer calls for them).

You can just post down to header over the windows, bring your point loads all the down to foundation/footings

buletbob

AFRAME seems to have some good points. you are going to have to install a structural ridge which must be designed for your area of load. I would think your going to have some steel plates laminated between some LVL's. size depends on the engineer. BOB

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Joe Carola

You obviously have no idea what you're doing as far as framing. Why are you trying to design this and not an Architect?

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Joe Carola

remomarc

6-12 cathederal?

Joe Carola

What's wrong with a 6/12 cathedral?

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Joe Carola

Thompsy

Yes, I don't have much experience building roofs using a ridgebeams , Usually I just through trusses up-- so much faster. I only build about 1 "camp" a year.
I'm thinking with this job it will probably more cost effective just to put up scissor trusses.

Yeah I know what your saying Joe, but I love designing things myself.....I even designed my own foundation using treated wood trusses. Two guys can put these trusses up in one day and be ready for walls.... No concrete needed