Polyiso question

[ponjohn]

If I use poly to insulate garage ceiling between the rafters ( against the outer sheathing) do I need an air gap?

 

[stm317]

Wood decking with asphalt shingles, or metal with no decking?
What kind of ventilation do you have?
Will you be completely sealing every seam with spray foam to create an enclosed building envelope or not?

 

[ponjohn]

Wood decking with asphalt shingles, or metal with no decking?
What kind of ventilation do you have?
Will you be completely sealing every seam with spray foam to create an enclosed building envelope or not?

Asphalt / plywood
Soffit vents
no, not a complete seal

 

[stm317]

Yes, you want an air gap