Take a look at these two elevations, showing a shed dormer springing out of a roof. The line near the top where the two roof planes meet is a little ways down the face of the main pitch. IMHO, this is done with a purpose, as a shed springing from the top ridge doesn’t look as good to me as this.
The ridge member is structural, as the space below roof upstairs is vaulted, mostly. A little run of joists is packed right up under the ridge to flatten the ceiling at the top.
Per spans and loads, the ridge, which gets picked up at center with a bearing wall, could be a 1.75×16 LVL, but we might do an 18, and frame things like this. Is there an easier way?
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That is how I do it.
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My shop has two sheds that start about 4 feet down the main roof plane. Each shed has a header of its own to carry its own rafters. Due to the height of the main ridge and the pitch, I decided that the dormers would look better inside and out done like this. Give some thought to the ceiling planes inside using your detail.
Recently built a house with sheds that generate from the main ridge. We laid those rafters out carefully so that the ridge cap (metal roof) would cap both the main ridge and the dormers without getting distorted and without requiring a pitch change flashing. One of those little things the owner never sees unless you do it wrong. The roofer dug it.
I will second Piffen's response.
And then, if you all will indulge me further, consider the windows in the face of the dormer, jammed right up against the roof. We want these under-the-roof interior spaces to have character, right?
Here is how we might address those window openings, and the need for headers above them. The LVL shown here is much more than adequate for the loads.
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BTW, I clipped this pic from my screen when in Sketchup using a cool little program called MWSnap. It is a free download, and very handy. File it in your tool kit right next to Irfanview.
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
In my shop, the dormer walls have 4x6 top plates that are also the headers. The windows are jammed right up under the eaves. The casement sash clear the bottom of the fascia board by a hair. Careful layout to maximize the rough sill height... but not too high.
I would drop the lvl to the bottom of the doubled plates or at least one plate, depending on the overhang projection needs.
Yes, I have made the header that way, or when there is a bit more lelvation and I wanted some overhang for soffit, I have framed the wall with a continuous header/top plate combo.
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Gene,The window location is going to be a function of the dormers overhang. If you jam them right under the plate like that your overhang might return right into the window. . .First locate the overhang and work down from there adding in any trim or exterior detail.http://www.josephfusco.org
http://www.constructionforumsonline.com
Edited 9/14/2008 3:33 pm ET by Joe
Thanks, Joe. I realize that I might have to pack down the RO head from doubled plates, depending on the o'hang, soffit, and frieze detail.
I am just thinking through structural considerations now.
This house as designed by the archie has great Greek revival details, as can be seen in this pic. You need to ignore the fly.
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The line drawings depicting elevations suggest that the more massive roof edge and frieze done for the lower roofs, is lightened up for the shed roof's edges. This may be common in Greek revival exteriors, but I don't know. Here is a closeup of what is shown for roof edge stuff, and you can see the difference.
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
Gene, all this great Sketchup talent and you don't know enough Photoshop to clone out a fly?!
You also need to ignore the fact that the roof extend should have reached over the faux pilaster trim box for the illusion of beam sitting on post. Somebody hada their head Up their **** on that one.
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You are right, but the stuff to the R of the pilaster all gets demo'd when the phase 2 addition goes on. A wall tie-in goes where the pilaster is now.
The builder should trek on down the coast from Blue Hill and look you up, maybe learn a little proper Greek revival trim stuff.
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
I'm available to consult.
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True. Faux loadbearing is just as important as true loading visually.
this has examples what I mean
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