I am analyzing a roof section to confirm a moisture failure. The roof section consists of asphalt shingles, bituminous paper, plywood, open-cell spray foam, air layer, and gyp. bd. interior. I first used air without addit'l moisture capacity and was getting hundreds of convergence failures. I was advised to change the air layer to the type with addit'l moisture capacity and that brought the convergence failures down to 28. I'm not sure how reliable these results are with that many convergence failures. I reduced the run time to one year. I'd like to run it over 3 or 5 years. Do you have any advice on how to bring the number of convergence failures?
I am also running a model with the same components but with an air layer added between the plywood and spray foam and am having the same issue. Any help would be much appreciated. Thanks in advance!