Vapor barrier in ceiling

[Daaaaaniel]

Hi,

I am renovating a house from the 70s that needs some love. I plan to fix the ceiling, where I intend to lower it to install spotlights in the closet.

Current construction, from top to bottom:
Roof trusses - insulation between
Lattice panel
Plastic
Ceiling (some form of ceiling panels in masonite maybe!?)

Thus, there is a small air gap between the plastic and insulation.

Desired construction, from top to bottom
Roof trusses - insulation between
Plastic
Joists
Plastered ceiling.

In the desired construction, there is no air gap between the plastic and insulation.
But maybe it's not needed?

An alternative would be to place the joists on the lattice panel, but by removing it and placing the joists directly against the roof trusses, the net lowering is less.

// Daniel

 

[hscn]

Your proposed solution does not imply any deterioration, rather an improvement because air movements in the insulation layer are not desirable.