House was built in 1980 and there are no blocks between the trusses in the attic or garage. Was this requirement?
I thank you for your help in advance.
Hi. Mike;
Blocking may be part of the truss bracing system, but it is more likely to be used to transfer lateral diaphragm loads from the sheathing or roof deck down to the shear wall or drag strut below. Blocking may be accomplished using diagonal straps, a brake metal shape, or an actual truss to transfer these loads.
Marcel 
No, it was not, around here at least.
Mike,
Depending on design (and if pre-fab’d) many (not all) truss manufacturers require blocking. The only way to know (for sure) is to read the truss certification (1980–good luck).
At this point, I might make note that none were in place, assuming everything else looked to be in order. May not be an issue. If there are other concerns, it can be evaluated with them.
Jeff
need truss layout to determine. Note in report if you feel you must.
Thanks Guys
I went ahead and called it out but noted that it may not have been a requirement…further eval by contractor if desired.
The seismic requirements in California most likely require solid blocking at the ridge and at all exterior bearing walls.