ISO Insulation

[Swamp Creek]

I have several used sheets of ISO insulation (got for free). I am going to use this material to insulate the floor, walls and ceiling in my wife's she shed. The sheets have a felt paper facing, do the sheets require a vapor barrier? Being used there are a several holes from the fasteners in the sheets. If the paper is a vapor barrier I was wondering if plugging the holes with silicone would be enough? So do I need a vapor barrier?

 

[billconner]

I assume you have polyisocynurate? No foil facer?

Primarily heating or cooling climate?

I like installing this gapped - like a 1/4" - and sealing joints with foam in a can. should provide a very air tight membrane. Seal nail holes same or a tape.

 

[Swamp Creek]

Yes the sheets are polyisocynurate with the black paper facing. Cold winters (Montana) and getting hotter summers (this summer really hot). So this paper facing will provide a vapor barrier? Any problem stacking a couple of layers between the floor, ceiling joist or wall studs? thanks