Second Layer Reroof Less than 3 psf Procedure

[waytsh]

I have a client that would like to perform a metal over metal reroof on an existing commercial steel building. The second layer of roof is less than 3 psf. IEBC grants an exception when the second layer of reroof is less than 3 psf, but what exactly does this mean? Does this mean that they don't need to involve a structural engineer and can just proceed with the reroof ? Does it mean that a full scale investigation of the building is not required to ensure that it complies with the current code but an engineer should still do a visual inspection of the building to make sure everything looks sound? Curious how you all are handling these situations.

Thanks!