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Insulation on 1/4 inch drywall

michaeldrehl's picture

Hi, I have a house that had plaster and lath ceiling. There was another ceiling created with 1/4 inch drywall and 2x4 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. 

Any thoughts?

Thank you for your help.

Best advice. (post #216203, reply #1 of 3)

Get rid of the drywall ceiling. Repair the plaster. Insulate above.

Second best advice. Insulate above the plaster. 

1/4 drywall will sag under its own weight if it hasn't already. 



? (post #216203, reply #3 of 3)


It's very unusal to use 1/4 (post #216203, reply #2 of 3)

It's very unusal to use 1/4 inch drywall. Mostly it's used when laminating over en existing surface or as  two layers when you need a curved surface. Are you sure its 14 inch and not 1/2 ? 

If you trust the framing you could go over the 1/4 inch with 1/2 inch drywall. I would not suggest trying to snake in batts of finsualtion through the hoels you willnot get 100% coverage. Rather try blown in cellulose or spray foam.