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Re: WOOD: "Economical Spacing of Rafters/Joists"

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Bill,

        In Calgary we also use a spacing of 19.2" (96/5) occasionally.  I
have seen this used with Trus-Joist wood I sections but not with standard
residential roof trusses.

Regards,

H. Daryl Richardson

Gary Hodgson & Associates wrote:

> Bill
> We almost always use 24" spacing up here in a roof.  We
> don't get your winds, but we get an awful lot of snow--near
> Buffalo.
> Gary
>
> On 17 Aug 2004 at 15:42, Bill Polhemus wrote:
>
> > I will probably get around to doing this myself but I thought maybe
> > some of you have already been through the exercise and have your own
> > opinions.
> >
> >
> >
> > As far as roof and ceiling framing is concerned, I tend toward a
> > "standard" 24 inch spacing for the rafters and joists, use No. 3 SYP
> > is possible and choose depths accordingly. Contrary to what some here
> > have opined regarding "wind uplift," when you are doing a home in the
> > Houston metro area, a rural location here gives you AT LEAST 110 MPH
> > (3-second gust) and Exposure "C", which can really kick the h*ll out
> > of a rafter with a long span, so the depth becomes an issue. I tend to
> > like 8' nominal myself.
> >
> >
> >
> > Anyway, just had an architect send back my plans, with the comment
> > that "you've got 24 inch spacing, we always use 16 inch," and "why are
> > you using 8 inch deep rafters? 6 inch should always be 'good enough.'"
> > That was the essence of his complaints.
> >
> >
> >
> > Of course, the latter issue is influenced by the former-he didn't seem
> > to have considered that at first, but as we talked he saw what I
> > meant. However, to him, 24 inch is just "not done". When I asked for
> > his reasoning he said "roof deck spans better," etc. 'Course, if the
> > roof deck is selected as per the code, this is a non-issue, but I
> > don't like to disappoint a client so I deferred to him on it.
> >
> >
> >
> > My point was that I thought a 24 inch spacing is more economical, even
> > if you use 8 inch joists as opposed to 6 inch.
> >
> >
> >
> > I'd like some input from others here on this question, limited
> > initially to the economic comparisons.
> >
> >
> >
> > If you want to pontificate further on other issues as to why one
> > spacing would be preferred over another, feel free.
> >
> >
>
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