Hi, I have a house that had plaster and lath ceiling. There was another ceiling created with 1/4 inch drywall and 2×4 screwed in the wall. There is a feet of space between the plaster ceiling and drywall. I wanted to place or slide fiberglass insulation in the ceiling from the top in attic space. From the attic, I see that the plaster has large gaps and wholes. I would cut a linear opening in the plaster and slide the insulation. My worry is that since it is a 1/4 inch drywall, the fiberglass insulation will cause it to sag.
I’m thinking of using R-13 batts. To lower the weight, I was thinking of ripping half of fiberglass off. Even with lower and half of the R-Value, at least there would be some insulation than nothing.
Thank you for your help.