We live in a 2 story house built in 1828 in SC. It has 10ft ceilings and most of the walls and ceilings are 10"to15" wide heart pine boards. The is currently no insulation in the house. I have been redoing a room upstairs that will be the master bedroom. I ripped the floor up and sistered plywood to the sides of the 4x8 beams. I am in the process of running new electrical wire for sockets in the bedroom and lights in the living room. The heart pine boards in the living room are nailed with cut nails into the bottoms of the beams, there will be 2 layers of 3/4 inch plywood on top of the beams covered with carpet, when the floor is finished. The heartpine boards in the ceiling of the livingroom will eventually be covered with 1/2" drywall. The living room and bedroom are the same size ~14x20 foot. After to electrical is done I want to insulate between the floors before the plywood is screwed down. I was thinking of using cellusoe between the floor. The exterior is old wood siding that was covered by vinyl. I am doing all the work myself so I will be doing small areas at a time. I will eventually remove the vinyl and wood siding, spray closed cell foam from the outside, and cover with plywood and tybeck. The main purposes of insulating between the floor are sound proofing the bedroom from the living room, and currently have no central heat and air. The house is heated by indivual propane heaters and cooled by window air conditioners. My questions are: Is celluose the best to use for between the floors for the purposes stated? Do I need a vapor barrier? Should the vapor barrier go below the celluose on top of the heartpine boards of the living room or between the drywall and heartpine in the living room. Does there need to be a vapor barrier on top of the insulation before the plywood and carpet are put down?

Hi All, Our house has a crawlspace, about 3-4 feet tall, with a concrete slab floor. A few years ago, we had the crawlspace walls professionally foam-sprayed with ~2" of closed cell foam ("Lapolla Foam Lock"), to an R-value of 13. Therefore, the crawlspace is (I think) now part of our conditioned space. I was down in the crawlspace the other day and realized that portions of the crawlspace ceiling still have some of the fiberglass insulation between the joists. I have read two competing theories: One is that there should be insulation between the ceiling joists (i.e., under the subfloor of our first floor above) even for such a conditioned space, in order to account for coldness coming up through the concrete floor. The second theory is that there should be no insulation between the joists because it is a conditioned space (it would be similar to putting insulation in the ceiling between my first and second floors, which I obviously just wouldn't do). Anyone have any thoughts? I know cold air doesn't rise, but the "stack effect" is something I've never really understood and don't know how it would affect this. Thanks in advance for any advice!