490sq.ft. Attic, square shaped with chimney in center. Previous owners laid down different types of insulation - blown-in fiber(2-4"), One side vapor barrier fiberglass(4" - R11?) on top of that. Portion of attic under highest roof is decked over(about 200 sq ft) so I have no idea how much/what is under there.

We live in southern CT - R38 territory.


What are my options: Remove everything, pull up center deck, and throw in 12" vapor-backed fiberglass batts for entire attic, and blown in under deck?

I personally don't want to put more insulation on top of insulation, just want to start over and do it right.

Thanks!

On Wednesday, August 6, 2014 7:12:58 PM UTC-4, wrote:
490sq.ft. Attic, square shaped with chimney in center. Previous owners laid down different types of insulation - blown-in fiber(2-4"), One side vapor barrier fiberglass(4" - R11?) on top of that. Portion of attic under highest roof is decked over(about 200 sq ft) so I have no idea how much/what is under there.



We live in southern CT - R38 territory.





What are my options: Remove everything, pull up center deck, and throw in 12" vapor-backed fiberglass batts for entire attic, and blown in under deck?



I personally don't want to put more insulation on top of insulation, just want to start over and do it right.



Thanks!

I'd start with what insulation is against the ceiling. It should have a vapor
barrier. For example, if it's fiberglass batts with the vapor barrier against
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 original
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 covered
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.