Here’s a copy of an email I received today.
I’ve enclosed an old standard WWTA installation detail sheet. On page 6, there is an over-view of typical truss roof framing details. The enlarged detail D2 on page 7 comes closest to describing the situation in your e-mail. I believe you are pointing out the 2x4 strapping connection to the actual 2x4 (on flat) hip ridge. These will come together on the same plane and won’t necessarily connect directly over a truss for support. The framers have probably added a “cleat” underneath the connection to strengthen this point.
The 2x4 strapping is spaced @ 24" o.c. The most that this connection will ever carry is 2’ of square roof loads - it’s really less than this because “H-clips” transfer the load and this joint connection would be the end connection of a 3 point multi span piece of plywood. You could probably get 2 or 3 toe nails into this connection which would be good for around 225 to 335 lbs.
You can work out the math backwards, but the 225 would be equal to around a 135 psf ground snow load, which is bigger than virtually anywhere except ski hills…
Bottom line; this isn’t anything to worry about. "
Keith Ohlhauser, P.Eng, P.E.
AcuTruss Industries (1996) Ltd.
2003-43rd St, Vernon, BC, V1T 6K7
Phone: 250-545-3215 ext. 2260
So there we have it. The Drop-in purlin truss would be over-kill.