I'm trying to go forward and complete an addition begun by the property's previous owner, and have a few questions concerning insulation of spaces. First question: The upper floor exterior walls are of 2x4 construction, 7/16 OSB sheathing, and 1/2" green foamboard (shiplap) caulked at each joint and around the perimeter. Foamboard seams are staggered. What insulation should be used on the interior of these exterior wall, R-19 faced or unfaced, and 1/2" drywall? Second question: The second floor has 3/4" OSB over 12" i-joist construction on 16" centers. Nothing else at present time. What insulation under the 3/4" OSB to get maximum protection. I would like to spray foam, but #1 -cost is prohibitive at this time, and #2-the insulators here are not willing to come and do a "small" job (approximately 500 sq. ft.). The project is about 25 miles from the nearest insulator. Thanks for your responses and advise. David.