Best way to seal seams in foam board?
We are building a vented roof over 16″ parallel chord trusses that will be filled with dense pack cellulose. The builder put 2″ tongue and groove XPS foam on the underside of the trusses as a thermal break. This will have 1x strapping as a base for a T&G wood ceiling. I want the foam to provide the air seal for the assembly but I’m not sure I trust tape to provide a long term seal on the foam joints. What is the best way to get this air tight? Thanks.
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