I’m stick building a gable roof, 28 ft between walls, with a center beam for joist support. I planned to use 2x10x16′ joists, staggered over the beam and spiked together. Now I wonder if the rafters not meeting the ridge board back-to-back is a problem since they will be offset by one rafter thickness, placing the ridge board in sheer. Do I need to do this differently? Butt the rafters together over the beam and tie them together with another piece of joist material?
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Tell me how they could possibly put the ridge BOARD in sheer when you ae not using one. You said you are placing them over the ridge BEAM
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My mistake, last sentence shold have read "...joists over the beam...", not rafters
John
Nail a block between the joists where they overlap (so there's a 3" offset in the joist layout, creating a 1&1/2" gap where they meet). Then line the rafters up with the block, so that they will be in line at the ridge.
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John,
They don't have to meet at the ridge at all. I always lay out the ceiling joist with one joist on one side of the mark and the other on the other side of the mark running right along side eachother at the center wall or beam nailed into eachother.
The rafters at the top of the ridge wont butt eachother, they will be nailed with one rafter on one side of the mark and the other rafter on the other side of the mark. It's that simple. I've done every house that way and never had or ever heard of it being a problem.
I ccan't imagine anyone saying that a rafter at the ridge that doesn't butt eachother and is nailed the way I'm saying it would have a sheer problem.
Here's what I did (started framing my roof this week).
I laid out the rafter positions on both outside walls first & matched them so that they would meet at the ridge.
Next I laid out the attic floor joists on one wall, I laid them out before the rafters, on the other side I laid them out after.
On the middle wall, I laid out marks that matched the rafter marks on the outside walls & put a 2x spacer since the joists are offset by 3" instead of 1.5".
This helped me keep the rafters in the right spot since I could drop a plumb line to the spacer & knew that the rafters would hit the ridge directly above the spacer.
(all this is assuming you haven't put in the attic joists yet)
You could also put the beam up in the ceiling and butt the joists to it. Hang the joist with Simpson’s joist hangers or compression blocking. I build girder trusses and block/hang the joist all the time. The ceiling is plain from wall to wall.