We are considering adding a sunroom on to our home on a 14'x20' deck using 2x6's spaced 16" apart...this is over a poured concrete patio and under an existing second-story deck...using the deck idea so existing 6x6 posts and footings can be used instead of busting up the patio and pouring new....we will use 5/8" sub-flooring and plan to install hardwood on this & heat with a pellet stove in the long winters here in WI....I'm wondering what type of insulation I should use underneath between the floor joists, vapor barrier recommendations etc....note that to have sunroom floor even with first-floor, there will be less than 1' of clearance under the 2x6's....any suggestions appreciated!