My house was built in the 60's and I have a very low pitch roof, maybe a 2/12. I have vaulted ceilings that seem to not vent at all because the drywall is against the studs and on the other side the decking is against so soffits and ridge do not seem to be helping.

My issue is condensation on the walls and top of the fireplace later in the day when it heats up outside. ( I Live in NE Ohio) The chimney has been flashed, capped and tuck pointed so I don't there is an active leak and ceiling don't show evidence of that. I just replace sections of them and they were not wet. When I ripped the ceilings down I did notice that the decking was very damp around the chimney and starting to get black. I have attached pics.

on each side of the chimney there is not way to vent and the upstairs hallway was starting to form mold due to condensation. I think this is a venting problem but don't know for sure. Could my flashing be too air tight? My roof is only about 6 years old.

I can get more detailed but wanted to see if anyone would reply first.

There was insulation in the cavity and I put insulation back.

Thanks!!!!!