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.
From: Richard Lewis [mailto:rlewis(--nospam--at)techteam.org]
Sent: Monday, March 20, 2000 12:31 PM
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?