Metal roof without vapor barrier on battens.

If a metal roof is installed over battens without vapor barriers does it really cause that much of a problem? If the house has a vented ridge, all vented soffit, two gable vents, and an air tight ceiling will moisture really be a problem? I don’t see how it could be but maybe someone who has seen this first hand could chime in. Thanks!

Depends on the climate, venting of the attic, insulation type, envelope layer, and a whole host of other factors.

The short answer is that in most situations where you hear of complaints of condensation, it is situations where metal is NOT installed over solid decking.