Here is a roof section the archy shows me, says it is framed with engineered trusses.
OK, I say, but who can build it, and how can it be transported here?
Here is a roof section the archy shows me, says it is framed with engineered trusses.
OK, I say, but who can build it, and how can it be transported here?
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Replies
>> but who can build it, and how can it be transported here
This is a very common truss for framing a dormer, and is called a dormer truss. Virtually any truss company will be able to engineer and construct this truss.
The big issue with this truss is the length. The drawing you show isn't clear whether the 50-ish feet is a clear span, or if the interior walls shown are bearing walls. If they are bearing walls, the truss will be broken up at the bearing walls and shipped in pieces and attached togther on site. If the 50-ish feet is a clear span, the length of the truss might be able to be shipped on a extra-long flat-bed trailer, or it may be abe to be broken up and assembled on site. This will be up to the truss mfg'er.
In any case, it shouldn't be a problem.
Bob
We can get trusses that long here. I have just placed an order for some 52' clear span trusses for an aiplane hanger. We handle the height with what we call "piggy back" trusses which is nothing more than a truss on top of a truss assembled on site using purlins on the top chords of the bottom trusses and then attaching the "pigs" with nails and scabs per engineered drawings.
Yours drawings seams to indicates 4 bearing points I believe which will make the job easier. There may be more than 1 way to build that truss so consult the designer to see which way is best suited for your job.
k
I agree. These shouldn't be a problem. Your questions are ones that the truss companys will figure out.
That's just an everyday situation for us. We call it a "broken back" truss.
The fact that it's over 14' tall is the only thing that's at all significant. I don't know of a truss place that can build anything that tall in one piece. The truss would have to be piggybacked and sent out with a cap truss.
The ~50' length isn't a problem. Trusses up to 60' are common. Trusses up to 80' can be built in one piece, but they're not as common.
Give me some dimensions and pitches, and I'll post a pic of what the truss will probably look like.
I decided to get in shape, and the shape I chose was a sphere.
Here ya go. Sorry for the funky fractions, but I didn't dream them up, the archy did.
This oughta give you a rough idea.Time is nature's way of preventing everything from happening at once. Space is nature's way of preventing everything from happening to you.
hey Boss
We build stuff up to 14' tall all the time. If it can be built without having to cap and is under 14' it saves money in the long run.
His truss was OVER 14' tall, not just close to it.
I generally cut it off at 13' 6" or so just to make it easier on the plant.Hillary said that one of the reasons she stayed with Bill so long is because no one can make her laugh like he does, especially when he says stuff like, "I did not have sex with that woman." [Jay Leno]
So how would you do this, Boss? The attached pic shows how the archy wants to do the main roof with trusses. He shows the large 20" deep "floor joist" trusses in a section, but leaves the adjacent 4/12 shed roof framing up to my imagination.
I had originally thought of stick framing the sheds, but I'll bet you will tell me how the truss engineer will approach it.
And here is my concept of the dormer arrangement. Look OK?
Seems to me I looked at something like that here recently? Did you post something about this recently?
I think in the other thread I said doing dormers with these kind of trusses was difficult. There just isn't much depth to work with. The drawings you show probably won't work for that reason.
I'd suggest building walls on both sides of the dormers. And putting beams under them so they're bearing. That takes much of the difficulty out of making the thing work.Everyone is kneaded out of the same dough, but not baked in the same oven. [Jewish Proverb]
I did not show the dormer walls. The trusses that appear floating bear on the walls. Until we get out to the walls, though, the inside dormer trusses bear with hangers on double "girder" trusses, one on each side.
Will it work?
I'm really not sure whether it will work or not.
Trying to vault the dormer certainly complicates things.
Not having much depth to work with complicates things.
And even if the trusses are deep enough to work, hanging them off 4X2 girder trusses is difficult.
If the dormers weren't vaulted, and the shortened trusses behind the dormer could hang on a girder which would sit on the dormer walls, I'd say it would work fine.
But as it is, someone would have to spend a great deal of time trying to work out the details. That's more than I'm willing to do here.Hillary said that after Clinton admitted to the affair she yelled at him. She said "Why did you lie to me?" And he said "You mean this time?" [Jay Leno]
The truss would have to be piggybacked and sent out with a cap truss.
Wouldn't a pair of inverted scissors-style trusses be simpler? Probably not, goes back to whether or not we have a free span . . .Occupational hazard of my occupation not being around (sorry Bubba)
Probably not.
With the inverted scissors, you MUST have 2 bearings on both halves of the building.
In most cases like the one originally shown at the beginning of this post, the trusses cantilever out over the porches in front and back of the house.I now qualify for the witless protection program. [Adam Rifkin]
MUST have 2 bearings on both halves of the building.
Yeah, that's what made me doubt myself. Second-guessing my self, today, a person might could have a 'high' and a 'low' structural ridge beam to carry the back-to-back inverted scissors. Would only work if there's a clean endgable to carry the beams. Like you pointed out, the vaulted dormers make this a complicated structural model. It's probably a much better canidate for SIPs.
the trusses cantilever out over the porches in front and back of the house
Yeah, I was thinking to 'simplify' the design back to the outside walls, and stick build the cantilevers, but that was partially due to all of the dormer "penetrations" in the roof shape.
I've had to start crash-course learning Architectural Desk Top. It has an abominal roof modeler, in terms of replicating practical construction. Not per se the software's fault, just that you can create a 'typical' construction and apply it in atypical ways. So, I'm trying to find way to make sure I don't create unbuildable volumes.Occupational hazard of my occupation not being around (sorry Bubba)