I'm looking to insulate a "crawlspace" in a room in my house. This part of the house was built directly over the ground on pillars (piers?) with about a foot of space between the floor and ground. During the winter tons of cold air comes through and causes the floor in this room and the adjoining room (also with crawlspace)to feel cold. Currently I have removed mouldy linoleum (?sp)and will be replacing some spots of rotted underlayment - the underlayment is in boards on not plywood, this is an old house. The beams are in surprisingly great shape. How can I go about adding insulation? I know I have the option of ripping out the entire underlayment and putting down strips of insulation over plastic laid on the ground, but except for two small spots the underlayment is in very good shape and I'm reluctant to rip it all out. Any other options out there? Maybe blown in cellulose? Thanks for any assistance!