Attic Insulation Mess

aid down different types of insulation - blown-in fiber(2-4"), One side vap or barrier fiberglass(4" - R11?) on top of that. Portion of attic under h ighest roof is decked over(about 200 sq ft) so I have no idea how much/what is under there.

n 12" vapor-backed fiberglass batts for entire attic, and blown in under de ck?

want to start over and do it right.

I'd start with what insulation is against the ceiling. It should have a va por barrier. For example, if it's fiberglass batts with the vapor barrier agai nst the ceiling, then I would leave it there and put either unfaced fiberglass batts going in the opposite direction, or blown in, on top.

Also, what's in the open areas that's close to ceiling, ie likely the origi nal stuff, is likely what's under the covered up area. Depending on it's thickness, it's probably not practical to do anything with the areas covere d with plywood. If there is already a reasonable amount, filling up most of the joist space, there isn't going to be room enough to do much additional good and it may not be worth worrying about.

There is roughly 2-4" of loose insulation beneath the existing down-faced batts. The vapor sides have been slashed for placement on top of existing insulation.

The issue of what - if anything - beneath the decking, remains.