I need to improve ventillation in my attic. Condensation is evident in the attic on the inside of the roof. I am planning to do so using soffit vents. But here\are some relevant facts and complications:
I live in Wisconsin. We have had ice dam problems 2 years in a row.
We use the attic for storage and the attic has a floor in it. The cavity below it accommodats 6-7" of insullation. We need to replace it because it has gotten wet due to an ice dam
Question no. 1: Which insullation would provide best R value per inch while being a bit moisture resistant? I don't believe that moisture will be 100% eliminated
Since we can only get an R value of about 20 from floor insullation we would like to put r-19 insullation loosely attached to the roof rafters. THis would allow air flow, but I think it would also mean that we would need 1 soffit vent per 'compartment'. There are 11 such compartments on each side of the roof. Some contractors say we would only need 3-4 vents per side of roof (23' long). But with the strips of insulation (even if loosely attached and with air space between inside roof surface and insullation bats, woulnn't only the ones ('compartments') with the soffit vents be ventilated. The rest might still suffer from condensation, no?
There is a roof ridge vent running alon the entire length of the roof and 2 small windows in the attic
Total attic area is about 400 sq. ft.
Any advice would be greatly appreciated. If I am not asking the right question, what should it be? Every contractor seems yto have a different opinion on what to do.