Replies

1. 
   Jay_ | Apr 13, 1999 09:26am | #1

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   There really doesn't seem to be enough information here.
   "are attic joists sufficient?" not knowing what they are, I'll have to say No, to be on the safe side.
   "Best way to tie into the ridge" seems to me that metal hangers would be best, but the real question is, is the ridge beam adequete, since a large shed dormer means that the roof structure is no longer a triangle, the ridge beam will have to be load bearing.
   Since I calculate the ridge is only about 10' high, if you want to be able to stand up at the outside wall, you will have damn little pitch in the roof, I can't see any more than 1.5:12 and that's with minimal head room, 1:12 is more likly.

   Jay

1. 
   Dan_Cimaglio | Apr 14, 1999 10:20pm | #2

   *Thanks Jay! Attic flr. joists are 2x6(no surprise) but the kicker is there is no ridge beam the rafters but up at the peak and they're 2x4's! I could install a new ridge beam the length of the dormer or the length of the house since they're tearing the roof off anyway. I'll use metal hangers anyway. You were right about the 10' from attic flr. to peak. They're aware of the headrm. problem at that outside wall. I'm thiking a 2:12 might do it. Back at you. Dan.

2. 
   Dan_Cimaglio | Apr 15, 1999 08:35am | #3

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   Going to enlarge an existing shed dormer on a story and a half 30's wood frame. It will run 20' from gable end and 15' out to ext. wall. House is 30'w.x36'l. Roof pitch is 8:12. The rake at the gable end and the soffit both extend 1' so the ext. finish should be pleasant to the eye. I'm headed back to meet the plumber so i'll take some closer measurements then. I'm keeping in mind egress, headroom,live and dead load issues. I'm in Oregon so snow's not a big issue but rain is.
   So the roof needs to be pitched. Tying into the ridge and enough support from the existing attic joists are my questions right now. Best way to tie into the ridge and are attic joists sufficient?

3. 
   Guest_ | Apr 15, 1999 08:35am | #4

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   Dan

   Was part of a similar job some years ago. Building department made us fabricate a continuous 16' or 18'-4.5"x12"(?) ridge beam/purlin, piece by piece up under the existing ridge, before being
   i allowed
   to install the new shed dormer rafters, which sat on the old roof at the ridge line, closed it in and then removed most of the old rafters and sheathing from inside the new dormer, tying back the remaining rafter tails to the new beam/purlin. The new ridge beam had to have contiuous load distribution down through three floors to the basement/foudation walls. Lot of screwing around for a bedroom and patio door onto a roof deck.