Hey Fellas, When you frame a gable end wall and you are using scissor trusses does a stud have to go up to the ridge to keep that outside wall from bowing. Or are gable pins enough? 8ft walls,wall spans 22ft, 6/12 on the truss 5/12 on the bottom cord. (2×4 walls)
Thanks, Lou
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Replies
Not sure I understand. I don't know what a "gable pin" is. I've always used a gable end truss as a gable end for a scissor truss roof.
You'll undoubtedly get more input.
"Doubt is not a pleasant condition, but certainty is absurd."
~ Voltaire
You be right. If he didn't order a gable end truss, he can just build his 8' wall and in- fill above the plate to the bottom cord of the truss with cripple studs. With a truss he has no live load path on the gable end wall.
Dave
His question is about lateral deflection. I agree, no load path is needed vertically.
BUT, I wonder about the lateral bending resistance of the double top plate at 8'. If there is an interior wall(s) intersecting and bracing the gable wall, I wouldn't worry, but if not, that's 22' of only double 2x4 to resist flexure of say, a big wind or a door through that wall slamming.
A couple of 11-12' studs from the toe plate to the peak would really stiffen up the wall in lateral bending; having only half the effective span of the horizontal top plate.
SO -
If the 22' wall has no intersecting transverse walls, I would definitely run all the studs plate to truss. Less wood, anyway. Add a metal strap on both sides at the 8' level if yer worried about spreading (if Boss didn't design the trusses!)
Forrest
I thought of that also, but what is the chance of that wall not having a window or door centered in it?
Still your right. A couple of double king studs on each side of a window or door going all the way to the bottom cord of the truss would be better for wind deflection.
Dave
I would hope the OP is talking only about needing balloon framing to the truss and not that he has scissors of that size for the entire roof.
There is not enough depth in his configuration to even construct a scissors truss -6/12 top chord and 5/12 bottom chord yields a might long scarf cut and what amounts to a simple hinge at the apex. Draw it out.
Regarding the suggestion to use cripples above a standard double top plate at 8 feet. Not too long ago there was a similar thread. The recommended solution, and a requirement in my neck of the woods, is balloon framing up to the rafter or truss to avoid the hinge point of a top plate in the wall field.
A ceiling diaphragm coupled with truss bracing or rafter blocking helps keep the gable from flopping about in the wind.
I have done this a few times. Attach a top plate to the under side of the bottom chords of the truss. Stud up to the plates you just attached then sheath the whole assembly.
have a good day
Cliffy
Thanx Cliffy, Thats what I'm doing. that seems the best way.
-Lou
When in doubt be a stud. The answer to any weight/bearing problem is transferring the load to the foundation.
By the way, we're looking for a diffuser and return grate to a 50'sh apt. high rise in-cabinet convection air conditioning and heat system. Top surface is 4 1/2" X 50+" with a return grill 52" x 16-18".