adding skylights to vaulted ceiling


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Old 01-18-10, 09:47 AM
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adding skylights to vaulted ceiling

For simplicity, our main room is currently 10' by 20', the room is a living room/dining room.

At some point in the past, it was expanded from an original length of 15' to 20' long. We found that the ceiling throughout was false so we decided to start tearing it down to raise the ceiling from 7' to 8'.

Now, in the front, where i mentioned was expanded by 5', the builders actually made that ceiling area vaulted.

So, this inspired us to want skylights. We ideally want two of them. However, the expansion seemed like a DIY project because the rafters are not exactly 16" on center.

In fact, the two areas we wanted the skylights, the rafters are 15.5" and another about 15" on center.

So, my concern is that skylights are wider than 16", at least as far as I can tell we would be looking at skylights that are 22" in width.

Being one, or two skylights - will this be as easy as adding header/footers just like you would when building a door/window - just at an angle? or, with this being a vaulted ceiling, do we need to consider adding additional support somehow?

With the space in the ceiling, if we had two skylights the header/footers for each skylight would be tied into a single rafter for one side of each window - is this too much stress for a rafter?

I can provide some webcam pictures later on if needed.
 
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Old 01-18-10, 10:50 AM
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One more item I am unsure about.

Soffits and ventilation - since there is not attic with the vaulted ceiling - should I be concerned with soffits? This particular roof does not connect to any other roof in the house, and certainly not the 'attic'.

There is however, an exterior vent that looks like it was there for air ventilation for that area - the original ceiling was flat though i.e. the insulation was against the drywall and the drywall was not vaulted - so maybe there is no longer a purpose for these vents now?
 
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Old 01-18-10, 11:37 AM
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To vault the rest of the room that was built with ceiling joists, you need a structural ridge beam, not a ridge board: Graphic guide to frame construction ... - Google Books

In that same book on page 136 is an illustration of the skylight rafters. Headers and trimmers at/over 4' must be doubled. At/over 6' must have hardware, per code.
Rafter ties are required every 4' when the ceiling joists run parallel to rafters. You cannot remove the ceiling ties without adding a structural ridge beam, either solid wood or engineered wood or steel. You may be able to add structural rafter ties at the wall height with required added nailing, every 48" apart. I suggest you contact your local Building Department and Homeowners Insurance if changing roof structure. This has serious potential for failure if not done properly.

Also, venting the bays above and below the skylights would be of concern to prevent ice dams. (Not only have the walls lean out and roof come down).

Be safe, Gary
 
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Old 01-18-10, 12:53 PM
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Thanks for the response gary,

at this point I can say that the vaulted ceiling I am talking about is similar to the "simple-span roof".

The roof starts at the exterior wall the climbs up to and is nailed to the 'original' exterior wall of the house.

Ill get pictures up later, but here is a paint drawing of the basic idea - sorry no cad skills.

http://dl.dropbox.com/u/1491001/drawing.JPG

The "Left side of the House" is 5 ft in length
 
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Old 01-19-10, 04:36 PM
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I've researched the issue a bit more, including the book gbr has suggested and here is what I think would occur; first some photos.

http://dl.dropbox.com/u/1491001/full.jpg
http://dl.dropbox.com/u/1491001/before.jpg

And here is a photo as to what I imagine would go down for the rafters. Each red line implies a 2x6 rafter. I am assuming in this photo that the skylights will be too wide for the space between the current rafters. The black line implies that particular rafter would be removed.

http://dl.dropbox.com/u/1491001/after.JPG
 
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Old 01-19-10, 10:27 PM
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I didn't realize I was answering the same post. My answer is: adding skylights to vaulted ceiling - DIY Chatroom - DIY Home Improvement Forum

Be safe, Gary
 
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Old 01-20-10, 07:24 AM
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Yeah, i tend to post to more than one forum in the attempt to get multiple viewpoints.

but i've also noticed that many people are doing the same thing so it's the same viewers...
 
 

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