[mmhendrie]

got a problem - i'm installing 15 inch wide insulation into a flat roof from underneath. I know I need to keep an inch gap on top of the insulation, that stops me from tacking/stapling the insulation up there. However, my joists are 20 inches apart at center.

So, I need to cut an extra strip to supliment the 15 inch wide - but how do i get it to all stay up there until i hand the ceiling. I'm afraid to ask if packing tape is okay?!

 

[Ron6519]

They have wire support rods that you can use to hold up the insulation. But it's going to be a pain to install the insulation the way you've planned. Personnally, I would have bought the wider insulation and cut it down for a friction fit. Either way I''d have the rods installed.
Ron

 

[Maintenance 6]

I never used packing tape, but I have used duct tape and a stapler. Used nylon strapping made to hang ductwork too. I can't see why packing tape wouldn't work. I assume you already have the 15" or I'd say use 24" and cut it down. It would make a tighter job.