Originally Posted by Ryland
I've added insulation to small rooms before and found it to be worth while, I felt that using foil faced foam gave the best results, also if you pull off the old dry wall you have a chance to seal up any cracks and gaps and that is a big part of installing foam as well is sealing up cracks at the same time.
Your attic insulation, the fiberglass will allow more air flow then cellulose does, so pulling the fiberglass in to the center and air sealing where the ceiling meets the outside walls, then adding blown in cellulose will help more then just going over top of the fiber glass, fiber glass doesn't slow drafts as well as cellulose and expanding foam will stop drafts.
I really should have caulked before adding the insulation, spray foam is a little on the pricey side for me. The insulation I added in the attic was left over from an incomplete project from my old house otherwise I would have blown in cellulose. The 36 24" batts werent easy to get through the 20" attic access door one by one