We built an addition to our house which was finished in 2015. For the top floor we used attic trusses with a 12/12 pitch. We’ll phase 2 came along which was replacing the old 4/12 roof with a 12/12 pitch roof on the original part of the home and our structural engineer  required us to sister two of the trusses in the addition where we made the connection.

It sucked b/c we had to remove finished walls. But glad we did, b/c we had mold on the underside of the roof deck. So, we just removed all of the horizontal drywall and confirmed it was everywhere on the north side. Noting on the south side. I attribute that to the sun. 

the insulation scenario was as follows:

flat part of ceiling-r49 bat
sloped part of ceiling-4 1/2 poly iso leaving 1″ baffle
knee wall-r19 bat

The long and short of it was that the installer packed most of the baffles with bat insulation on either side of the poly so airflow was severely restricted. Fortunately, the mold is mild and will likely be remedied by over the counter products (we have a testing company come in next week).

So, I’m pretty much done here. The company that did the insulation has agreed to fix it inkind, but I am thinking I it will be better to just spray foam the whole dam thing eliminating the the soffits/ridge vents and the need to even insulate the knee walls (yes the floors are insulated from wall to wall). 

The decking is OSB for this particular addition. I elected to use plywood on the 4/12 roof replacement but stuck with the OSB. The damage is minor by represents itself in almost every bay. My thought is that close cell spray foam will eliminate future moisture issues and I should be good from there. My questions are:

1. do they just fill the soffit holes with foam

2. do they just spray over the ridge vents

Anything else I need to be thinking about here?

Thanks