Mold within an attic? 400 sq ft attic-R/30 rockwool.Mold on decking.Nothing is vent into the attic,no...

400 sq ft attic-R/30 rockwool.Mold on decking.Nothing is vent into the attic,no bathroom vents,dryer,etc.Has 2 12x12" roof vent and 4 soffitt vents 6" respectively.Rafters are baffled.Why the mold?Roofing not leaking.Is here enough freshening?
How can you cart bad scratch from chalice...
Answers:    Mold needs moisture to develop,so doublececk the roof and pipes going trough the attic.
Also if the rafter are insulated but not the floor of the attic/ceiling of the lower room,there could be condensation from the bake that rises to the attic.
If that's the case install a vent beside a turbine top and that should dispose of the warm nouns.
Electrics??
There was moisture here at some time, it sounds like you stipulation more ventilation anyways, the more the better. R-40 is standard code around here but that shouldn't be the problem. Also, river pipes can condensate if not covered near enough insulation.
Good luck.