Hip Rafter Tributary loads
Hip Rafter Tributary loads
(OP)
I am trying to build an irregular hip roof and need to utilize hip beams. I had a program figure the point load at the ridge. My question is, when I design the support for the hip beam do I need to double the load for the other hip?
24'6" span, floor joists 2x8 @ 12" O.C. The hip beams will need to be supported by 4 2x8's. if I am accounting for the single load, one of the supports will need to be cantilevered 1ft and then supported by 4 more 2xs if I have to design for double the load. 463lb LL and 271 DL at the hip / ridge connection (I am assuming this is only one of the hips). Single 2x8 hip and 2x6 rafters @ 24 O.C.
Any help would be appreciated.
24'6" span, floor joists 2x8 @ 12" O.C. The hip beams will need to be supported by 4 2x8's. if I am accounting for the single load, one of the supports will need to be cantilevered 1ft and then supported by 4 more 2xs if I have to design for double the load. 463lb LL and 271 DL at the hip / ridge connection (I am assuming this is only one of the hips). Single 2x8 hip and 2x6 rafters @ 24 O.C.
Any help would be appreciated.






RE: Hip Rafter Tributary loads
RE: Hip Rafter Tributary loads
You probably know this - but I see ridge beams with huge tributary areas for uplift simply toe-nailed into a stud-stack all the time.
RE: Hip Rafter Tributary loads
RE: Hip Rafter Tributary loads
RE: Hip Rafter Tributary loads
Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it
RE: Hip Rafter Tributary loads
Thanks for everyones help
RE: Hip Rafter Tributary loads
My question from your sketch is how are you supporting the top end of this beam (these beams)?
StruCalc assumes a pin connection at each end. From you sketch, I can't tell how you're addressing this issue.
RE: Hip Rafter Tributary loads
RE: Hip Rafter Tributary loads
Whether it's a truss or tied arch, the midspan concentrated load is the sum of the reactions of two hip beams and a short ridge beam. It also carries approximately two feet of uniform load.
Piece of cake. You don't need a computer to solve this baby.
BA
RE: Hip Rafter Tributary loads
Are you going to support the hip beams on a post at the top? Is that post itself going to be supported by a beam? If so, take care to ensure that the top of that beam is braced somehow. Presumably, it will not be braced by the roof sheathing.
RE: Hip Rafter Tributary loads
RE: Hip Rafter Tributary loads
RE: Hip Rafter Tributary loads
If the rafters are properly supported vertically, there should be no tendency for the walls to spread under gravity load. In a manufactured corner set, there would be bottom chords to the jacks which tie the rafters together somewhat at the ceiling level. If it's still an option, you might try to mimic that arrangement.
I agree with you, what you've proposed sounds excessive. I used to work as a roof truss designer back in the 90's. I don't think I ever came across that standard hip rafter that an end supported double 2x12 couldn't handle. And I used that at a ski lodge in Whistler, BC. Of course, you typical manufactured hip set is in the 8-10' range.
I'm sure that engaging the services of a local structural engineer would result in a more efficient system. Of course, the $500+ you will spend on an engineering solution may well offset the material/labor savings. Time is probably an issue as well.
RE: Hip Rafter Tributary loads