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here are some pictures to follow up with my original post. I greatly appreciate the information. Click to Enlarge 40.62 KB Click to Enlarge 47.26 KB Click to Enlarge 51.74 KB Click to Enlarge 89.36 KB Click to Enlarge 38.18 KB Click to Enlarge 41.16 KB

The furnace does not have a humidifier nor are any portable humidifiers are used. The bathroom fans are both vented above the roof line and the vent hoses seems to be securely attached and without any major leaks. I will investigate for any small leaks. The strange thing is that the bathrooms are located towards the east end on the north facing side and the black spots/areas seem to be most prevalant towards the west end of the north facing side. I would expect the problem to be the worse above the bathrooms. No black areas/spots are evident on the south facing side. I will post pics later when I get a moment. FYI, The ceiling has R-38 insulation with baffles installed. - Thanks, Cory

I have recently developed a mold or mildew problem (not sure exactly which one or how to tell) on the underside of the roof sheathing but only on the north facing side this 2 story home. The sheathing exhibits black areas/spots and there is a musty smell evident within the attic. The house was built in 2002 and has soffit and ridge vents although when the contractor installed insulation he covered the soffit vents with insulation and installed blue baffels between the rafters. The baffels begin at the soffit and extend about three or four feet up the roof line. I am assuming that the baffles are not allowing proper ventilation and that I should remove the insulation from above the soffit?? All fans are vented through the attic to the roof. I do believe that the cold winter coupled with an extended period of snow on the roof and the lack of adequate ventilation is causing condensation. Comments on the use of baffels and their adequacy and also what to do about the mold/mildew on the sheathing would be greatly appreciated. I have searched the forums and have found many varying opinions on what to do and whether or not to apply Boracare or similar or to just correct the ventilation problem and leave alone. I can provide pictures if needed. Thank you in advance for your time and help!