Insulating my old back house floor?
The back house on my 1910 New Englander (Southern Maine) is an old shed which sits 24" off the ground on a few (too few) concrete piers. I need to insulate underneath before winter arrives, because this building has a bathroom and laundry room in it. When I bought the house, the plumbing supply lines all ran under the structure, and had burst from freezing, including the hot water heating system. I have replaced the plumbing with PEX, and it is now all within the insulated envelope, and the rooms are will now be heated with 220 electric heaters. However, I want to insulate the floor so that the rooms are not freezing cold this winter.
I plan to do the following...
1) Install bat insulation between the floor joists ( 24" OC x 8" depth.)
2) 1/2" Ridged over the bats to help keep it in place, and to keep the critters out.
3) An insulated box around the tub trap, which sticks down below the floor joists. I also have the ability to drop a piece of heat tape into this box from inside the building if necessary.
4) Vapor barrier on the bare dirt under the building
5) Insulated, pressure treated skirt around the perimeter, to keep the wind from howling through underneath.
I should add that I intend to demo this structure within a year or two. If I did not need the bathroom and Laundry, I would probably just winterize the plumbing and not worry about it. Any suggestions? Holes in my plan? Am I overly concerned?
Thanks in advance!