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Re: Conventional Wood Framing

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The only mention of hip framing I can find in the IRC says:

"Hip and valley rafters shall be supported at the ridge by a brace to a bearing partition or be designed to carry and distribute the specific load at that point."

(And that the hip is a 2x and if the pitch is 3:12 or flatter must be designed as a beam.) That's it. No examples, no hip/valley rafter spans. No ties. Nothing. Magic. Actually, by that sentence, it seems that the answer to the original question about support of hip/valley rafters is that they must be supported vertically at the ends (the non-ridge end is presumed to be an exterior wall, I suppose).

I'm not picking on you, by the way, just pointing out that, if read and enforced literally, there are almost no houses with hips that meet the prescriptive code requirements. They can't - you can't require a point load distribution from a tributary area and then not give span tables. You're no longer prescriptive at that point, you're engineered. Now, I don't think it's a big deal if someone is building a 24x36 rectangular ranch, but most builders I know believe that if it isn't a commercial structure, it's covered by the prescriptive code. There's a lot of blissful ignorance of the fact that the market isn't building 1950s tract ranches anymore.

Jerry Coombs wrote:
Small homes can be done more-or-less prescriptively.  I believe the IRC discusses it.
But when I design high-end homes, I use the traditional engineering approach.  Rafters supported by perlins, braced by struts.  Struts are anchored to wall top plates.  Joists in tension contain the outside walls.  There are publications that prescriptively do some of that, but it's same as any other design.

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