How to Keep the Top Plane of Common and Hip Rafters in Line
I hope it’s okay to post a question to all your brilliant and experienced people that doesn’t specifically have to do with green building techniques.
I’m building a wrap around covered porch. House is 34′ wide. Porch will extend 12′ past side wall and 12′ along side wall, so outside edge of porch will be 46′ long on the front and 12′ long on the side (and 12′ deep). 6×6 posts along the outsider perimeter of the porch. 2×6 rafters. 4/12 roof pitch. 2×8 ledger board for rafters.
My confusion is in building the hip rafter, coming out of the corner of the house to meet the outside corner of the porch. That is, the hip rafter will cover off the corner of the house at 135 degrees from the front face and side face of the house, and will be 17.5′ long (4′ rise on a 17′ run (square root of 12 squared plus 12 squared)). I would like to use double 3×10 (yes, 3″; but really 9.25″ high) for the hip rafters.
So here’s where I get lost (although it’s certainly possible I’m lost already):
I need to keep the top plane of the 2×6 common rafters in line with the top plane of the hip rafter so that the sheathing lies flat.
I am planning to use hurricane ties for the 2×6 common rafters to the top plane of the rafters will be 5.5″ above the outer corner of the double 2×8 girders between the 6×6 posts.
That means I need a birdsmouth cut into the double 3×10 hip rafters, right?
If so, then the heal cut would need to be approximately 4″ into the 9.25, right?
Is this okay?
Here’s a picture.
I don’t claim to have any knowledge/skill/experience, so please don’t hesitate to tell me I’m wrong about everything (assuming I actually am).
Thank you very much!
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