Upside down attic insulation
Our 1500 sq ft ranch's attic is very under-insulated. During last summer's moving-in renovations all of the 55 year old windows were replaced, all cracks caulked, etc., making it pretty free of drafts. However the heating bills were still $400/month with the thermostat at 66F (oil heat - 30 year old furnace). The attic has a double layer of 4" fiberglass batts in place. The bottom batt is kraft-paper down, then the top batt is kraft-paper up. There's no vapor barrier, but during the renovations we used copious quantities of BIN shellac primer on the ceilings (to seal in cigarette smoke residue, ick) and I understand that makes a fairly decent moisture barrier.
If I were to go and add a whole bunch of blown in cellulose insulation to bring the R value up to around 40, should I either remove the top layer of batts, flip them over, or leave them alone?