From: "Barry H. Welliver" <wellive(--nospam--at)attglobal.net>
Date: Tue, 21 Mar 2000 07:04:34 -0700
With a light roofing material like metal the dead load should be a smaller
percentage of total load and perhaps creep concerns may not be as significant.
Two suggestions I'd put forth.
Is it possible to use a double 2x6 (one on either side of the truss top cord) to
provide additional strength?
Also, a continuous fascia detail may go a long way toward spreading out the
concentrated "roofer" load. I've been working with some Japanese detailing that
allows for very thin edge profiles. The test of time has apparently helped
develop these methods and calculations sometimes fall short of justifying why
they work. Then again, the Japanese counterpart to the American roofer may be
somewhat smaller. :-)
Barry H. Welliver
> I've seen many 5' to 7' eaves - all with problems. Remember to consider the
> effects of creep. In a year of so there will be no way to insure that the
> eave won't form a very unsightly edge as the eaves dip. Also, consider the
> uplift on the eave and make sure that this does not become a problem.
> Living in the desert, long eaves are fairly common but so are the complaints
> that go with them. You might want to explain this to the client and find
> examples in your area of the problem I just described.
> -----Original Message-----
> From: Richard Lewis [mailto:rlewis(--nospam--at)techteam.org]
> Sent: Monday, March 20, 2000 12:31 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Large eave overhang
> I am working on a wood framed project where the architect wants to have a
> 5'-0" eave overhang. Roof is a 3:12 pitch. The main roof framing members
> are prefab wood trusses @ 2'-0" on center. I was looking at using Doug-Fir
> No. 2 lumber. For a 2x6, using Cd=1.25 and Cf=1.3 I calculate an allowable
> moment of 896 ft.-lbs. My concern is with a roofer during construction, or
> renovation. The roofing material will be metal roofing. Using this design
> moment the maximum weight of a roofer standing out at the edge of the eave
> would be about 180 pounds. I don't think this is enough capacity for a
> roofer (please nobody take this personally).
> I can fiddle with the Cd value to a higher number, since the duration of
> Cd=1.25 is 7 days, but I don't gain a lot.
> What has been the experience of others on the list? Anybody design a 5'-0"
> eave? Anybody do it with a 2x6? What should I specify as loading for the
> truss manufacturer. I need to stick frame some of the eave at various
> locations. Any recommendations for or against using a 2x6 and hoping the
> roofer is not too heavy?