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Re: Residential construction-hip beams

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I have run into this also having originally starting my career in Denver then moving to the bay area.  We used to call it "California Framing".  Anyway once the plywood is attached and you have collar ties or ceiling joist attached to the rafters, the single 2 X hip and ridge perform fairly well..  However, how do you calc this.  I once tried calculating the system as a truss, but I had trouble making the connections work between the ceiling joists and the rafters.  Then what do you do at the end walls where the ceiling joists are perpendicular to the rafters.  I think you have to look at the roof loads, spans, and roof configuration and make your judgement.  I typically calculate the ridges, hips, and definitely the valleys as beams.   I have seen these "California Framed" roofs sag overtime.  Especially if concrete tile was involved.  Our firm was hired as an independent consultant on one of these frivolous lawsuits in the Bay area a few years back when an Condominium Association at the prodding of a maintenance outfit sued the developer over insufficiently designed structures that were "California Framed".  They found a colleague of ours who testified that the original design was insufficient to resist both lateral and gravity loads. (I hate those guys maybe another topic to discuss).  These units were in fairly good shape and this was 2 years after the Loma Prieta.  Well the case did settle and the roofs were strengthened.

Another alternative is to construct the roofs out of Pre-engineered roof trusses.

>>> domdean(--nospam--at) 07/23/00 06:19PM >>>
I would like to thank everyone for their response so far. I have been doing
residential design for about 12 years in New England. I know that when a
builder submits a "stock" set of plans for a hip roofed colonial, the roof
is framed with 2 x 10 rafters (depending on the span) and a single 2 x 12
hip. For a typical 28 foot deep colonial, the hip length would be
approximately 20 feet. With the triangular loading pattern and a snow load
of 30 psf (and a dead load of 10 psf) the single 2 x 12 would be grossly
overstressed ......***

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