Today we had the crew from Anderson Insulation come and blast this project with 3-6 inches of closed cell spray foam insulation. We hung some 1/2 blueboard on the upper walls to allow for the foam right above it, as the attic won't be fully insulated, but the envelope around this new library and the roof of the bedroom next door will be. Its often a challenge in older homes to retrofit insulation, but working with the foreman at Anderson, we determined this was the best solution for our cost/benefit ratio. Should be cozy.