I have a customer in Michigan who I completed a roof for several years ago and now we have a problem. The attic has lots of moisture in it which is seeping through the drywall into the living space. I installed a ridge vent and a previous contractor installed soffit vents but the insulation may be stopping the airflow somewhat. He also have gable vents and I am not really sure how this is affecting the airflow performance. This house is a 2 story chalet so there is not much insulation room and not a good way to ventilate it seing as it have 2x6 rafters and 6" of insulation. Can anybody give me some advise? The underside of the roof sheeting has moist mildew and has had it for a very long time and the customer wants to get it fixed???