When our house was insulated, walls with beads and new layers in attic, they made lots of new vents in the fascia board with the specific purpose of preventing attic timbers rotting by ventilating it, said it was part of the regulation, as we were unsure they put so many in it was like a hurricane blowing in the attic. We've always had condensation and mould even though house only built in 2005, but the insulation has made no difference either way. I think the windows are our issue , quality not great.