Hello all,

I know there’s a lot of information out there regarding these types of attics but I’m having a hard time deciding what’s going to be best but yet also still someone cost effective. Here’s what we currently have:

knee wall attic-

roof deck has original r19 batt insulation. There doesn’t seem to be any venting from the soffits as the soffits aren’t vented and there is no baffle in the back. I air sealed and insulated the knee walls with r15 batts, and am now realizing I probably wasted my time/money. 

wall/ceiling cavity –

has r19 batts running up through behind the drywall into the gable attic

gable attic –

has r19 on roof deck, unsure if anything else as there is no access. Eventually I need to make access. Has gable vents on either side and the ridge cap is vented as well. 

so my questions are – can I add polyiso rigid foam on the roof deck in the knee wall attic? With that, should I seal off the joist cavities where they continue on into the wall/ceiling section between attics with polyiso and spray foam? Seal off down below as well, as there’s no soffit vents? Is there any benefit in adding insulation between the lower level ceiling and the subfloor of second story? 

gable attic – just add blown in to the floor? Seal all light fixtures with spray foam? 

apologies in advance, I know it’s kind of all over the place. Thank you!