Normal commercial lay in ceilings have the insulation on the
ceiling tile. You can buy it as 2x4 batts, faced or unfaced.
Typical would be 6" faced with the VB against the tile (toward the
conditioned space).

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______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)




" wrote in message
...
Ive put in a layin 2x4' tile ceiling under what was a
cathedral
ceiling for my 24x16' living room . The heat gain to the living
room
was cut dramatically last summer here in Florida . I have a
space
above the drop ceiling about 3.5' feet in the center tapering
down as
you move away from center . Is it absolutely imperative that I
insulate (using batt insulation) the entire space above up to
the
underside of the roof ? And, must i put in a vapor barrier of
some
sort at the underside of the roof ? Your thoughts
appreciated.
Thanks.