I was thinking today that camber got mentioned a couple of times.
The first truss plant I worked at in the 1980s cambered trusses. Every truss plant since then has not.
I don't know what percentage of plants use camber. Just wanted to mention that it's not universally done.
Eng16080 said: "Most truss designers aren't interested in doing consulting work without there being a guaranteed job."
I'm sorry you've had that experience.
Every place I've worked at, we've been glad to help out. I figure if we can work out details ahead of time, it benefits everyone. And...
XR2500, you have a point. It might be possible to use a smaller BC size with a center bearing.
It depends on the situation. If these attic trusses go up against a 2nd floor that's framed with 2X12s and the floor heights need to match, that might determine the size of the BC.
In general, I...
XR250 said that adding a center wall will make the trusses cheaper. It might require smaller plates at some of the joints. But plates are a small percentage of a truss cost. On small attic like this one I'd say it would make virtually no difference.
StrEng007 said ..."coordinate with the...
A few thoughts and opinions from the perspective of a truss designer:
I've often wondered why more people don't put studs 2' OC under trusses in general. Less lumber used, and more space within the walls for insulation.
Setting the trusses 16" OC will increase the cost of the trusses by...
A couple of practical thoughts -
LVLs can be used as rafters. They don't face the same limitations as I-joists, and long lengths are no a problem.
A 7"x18" parallam PSL as the ridge beam was mentioned. Make sure what you're specifying is readily available. Large beams like that can be...
All the documentation I've seen for several brands of I-joists have all required a ridge beam.
I doubt the manufacturers would go for bolting floor joists to I-joist rafters. But I have never been presented with a situation like this one before, so I haven't asked.
"I get how compressive stress would be far higher under only self weight case and therefore more unstable."
You stated the problem perfectly. What's counterintuitive about it?
I don't have an example to post at the moment, but we do this sort of stuff all the time. In this case it sounds like a 2X6 vertical that's held up an inch (or whatever) would do the trick.
On a note that's not exactly related - I strongly recommend having adequate depth for the trusses. The...
I've heard some discussion that bracing the bottom flange helps control vibration. But I can't point you to specific reference that covers the subject.
On a 14' scissor you won't get too much horizontal movement. A truss supplier will gladly run a truss for you and give you a drawing.
Actually, I wish more architects and engineers would do that. It would save some headaches in the long run.
I'm in agreement with those that say the Simpson...
I don't mind the "harpoons" or arrows. As long as they're different for the joist spans and the joist runs. I've seen plans where they have arrows both directions. Then it's not always easy to figure out what's intended.
Best wishes for a full recovery.
My parents both had heart problems and had stints & bypasses. They both said they felt better after the recovery period. I hope the same is true for you.
I think the OP is misinterpreting what the document says.
The top flange is virtually always in compression when it's used as a conventional floor joist. So compression in the flanges isn't a problem.
The issue with them being used as rafters (with no ridge beam) is that the entire I-joist...
The OP asked: "Along those lines would you see any real benefit to stick framing the gable trusses?"
The only situation that comes to mind is an end wall where there are scissor trusses. I'd prefer to see a balloon framed gable wall from the subfloor up to the underside of the roof.
"As far as percentages go would you say you do more truss packages with or without gable trusses..."
A wild guess would be that 95% of our jobs have gables of some kind. The "wall gables" - Maybe one or two a year.
If you do drop the 1st truss in, be sure you have enough heel height to work with. Otherwise you might only have a sliver of wood out there for the truss to bear on, and it might not work.