Will blown-in insulation work directly on the back of 12" square ceilings tiles?

Question

We're renovating an extremely old house that we use as a camp that had numerous issues. ( Originally built circa WW2, but has had some work done since then. We use it occasionally in the warmer months but are looking to make more use of it on a year-round basis. )

The previous setup was fiberglass bat insulation and 12"x12" ceiling tiles surface mounted to furring strips. We removed the old ceilings and insulation due to roof leaks and rodent damage.

The furring strips are still up, and I'm considering placing a new 12" tiled ceiling to keep the original aesthetic. This would be stapled to the existing furring strips. However, I had also considered using blown-in fiberglass insulation to insulate the camp evenly and appropriately.

Assuming the ceiling tiles are appropriately fastened, can I blow insulation ( at approximately R30 ) directly onto them ?

Are there unforeseen issues with this ?

Answer 1

I can tell you that I did this exact same thing in an old commercial building and it did not work well at all. There was a roof leak that damaged a few tiles, and that wasn't a huge deal, but trying to replace them rained down insulation all over the place. Also, because of air pressure chnages in the area above the tiles, there were issues with them loosening up and falling. We think the weight of the insulation was a factor, but also the insulation being pushed by changes in the air pressure.

The bottom line is the tiles are very fragile and shouldn't support any weight. The whole ceiling had to be pulled down after 8 years or so and is being replaced with beadboard that will be much stronger. Looking back, even something as thin as 3/16 plywood underlayment would have made it much more resilient.

Answer 2

One big one... dust.

Normally, blown insulation is above a finished sealing (drywall or plaster, which provides substantial air sealing) and a vapor barrier. You'll have persistent severe glass fiber pollution if you do this without installing a poly barrier, at a minimum.