I am renovating my basement in New York. I have 2" thick r10(5x2") Owen Corning rigid foam board insulation covering the wall and Roxul 3" comfort batt insulation between wood studs. My contractor didn't put vapor barrier as he originally promised. He has still not covered all the walls.

Do I need to install vapor barrier?

  • What's the perm rating on your foam board, and where is it located within the wall assembly? – ThreePhaseEel Aug 14 '18 at 2:28
  • I am not sure about the perm rating. It is fomular XPS 250 R10 from Owens Cornings placed right next to the basement wall all around. Then I have wood studs and Roxul in between the studs. Thanks – Patel Aug 14 '18 at 2:46
  • @ThreePhaseEel, Water vapor permeance is 0.7 for 2" foamular 250. – Patel Aug 14 '18 at 3:32

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