Using Blue foam board on inside wall..
Marc5106
| Posted in General Questions on
Looking at a Mobil home in Southern Vermont..
Metal exterior..not sure if it’s insulated.
Paneling on the walls..
Metal roof..not sure if insulated.
Thinking to add 2 inch foam ( blue board) STYROFOAM™ Brand Scoreboard Extruded Polystyrene Foam Insulation to the inside walls..tapped… no vapor barrier.. 7/8 metal ferring..1/2 inch sheetrock..glued and screwed.
On ceiling… using 1 inch foam.. (blue board) taped.. no vapor barrier..to cover existing ceiling..then 1/2 inch sheetrock.. glued and screwed..will add 4 inches of rock wool on top of roof..under metal pitched roof that was added.
Thanks Marc
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At 2" XPS (Styrofoam TM) is a Class-II vapor retarder, perfectly adequate for a VT climate. (By Canadian National Building Code definitions it qualifies as a "vapour barrier".) At 1" it's almost into Class-II range, certianly nothing to worry about as long as it's air tight and vented to the outdoors at least a little bit on that built-over gabled roof.
The labeled R-value is R10, but over time it drops to R8.4 as the climate damaging HFC blowing agents bleed out over the decades. At the same 2" thickness foil faced polyisocyanurate would deliver R12- R13. Polyiso is blown with much lower impact hydrocarbon blowing agents too.