make a truss for contractor roof screw up snow load
make a truss for contractor roof screw up snow load
(OP)
snow load made contractor stick frame roof no good - rafters way overspanned. 147#/lf D+L+S applied to each 4:12 rafter (24" on center), 24' span, 2x6 rafter, 2x8 cieling joists. trying to come up with a good makeshift truss fix, tension loads a bit large for joist to rafter connection. here is what i have come up with. perhaps a manufactured plate would be better then simpson strap... any comments appreciated, i prefer to get at the project first and send it on off to the truss manufactures rather than trying to fix after the fact. attached is a quick ACAD file.





RE: make a truss for contractor roof screw up snow load
RE: make a truss for contractor roof screw up snow load
RE: make a truss for contractor roof screw up snow load
RE: make a truss for contractor roof screw up snow load
what may not be entirely clear from the crummy detial is that the two members - rafter and joist are not in the same plane (typical stick frame construction) so... the proposed new diagonal web butts into the rafter but nails into the joist. and yes the idea was to notch the vertical member into the ridge board (and butt against the joists - but use screws at that connection H9 simpson)could use a 2x8 to better handle the nails for all the new truss members...
yes, the straps are certainly need to be looked at, but i was planning to add a sister joist just to make the sides flush for the ps218 straps.
i realize there are spacing issues and edge distance issues all over the place at every connection... but the other choice is to throw in a steel beam (probably 30#/ft weight) or several wood beams and still have to kick up to support the rafters which seems like just as much work - you have to follow the new load path - and you have ugly beams at 7' high.
RE: make a truss for contractor roof screw up snow load
RE: make a truss for contractor roof screw up snow load
RE: make a truss for contractor roof screw up snow load
Also, is the ceiling joist one piece or is it lapped (which seems more likely)? Since all the pieces don't align, I wonder how much blocking will be needed.
Would it be possible to install a 14 or 16 inch deep I joist along side of each truss instead? Bearing length might be tough but I'm wondering about all the nailing and blocking (labor cost).
I suppose it's not polite to ask but... how did the roof get built without someone (owner, engineer, building official) noticing the lack of roof structure?
RE: make a truss for contractor roof screw up snow load
and you are right, 8 foot would make just as much sense. and i dont think there is any room for beam, and if there was you would have to kick up to midpoint to each rafter anyway = as much labor as truss??
update - they are running into more issues because of no permit - like zoning!!! heh heh.... the house was built without permit, so the contractor just built his "standard" roof stick framing that has "worked and never failed for 30+ years.... etc.. etc...", but he failed to realize that the load was effectively doubled because of snow...