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Attic insulation

Techman Member Posts: 2,144
what is the story with/without a vapor barrier in the ceiling in a 30-40 year old house. Does the vapor barrier make a difference in a loose vs. a tight envelope? Tks! I'm thinking about mold growing in the insulation.


  • BillW
    BillW Member Posts: 198
    Vapor barrier

    The vapor barrier goes on the bottom of the insulation batts,toward the occupied space to prevent moisture from there migrating into the attic and condensing.  Potential mold, water stains, insulation failure and a lot of other problems can result.  Moisture barriers are built into one side of the fiberglass batts, or if you are using loose fil, blown-in or other insulation, plastic membrane is used first.  Additional insulation, when placed on top of the existing insulation should not have a vapor barrier.
  • heatpro02920
    heatpro02920 Member Posts: 991
    Bills got it rite

    vapor barrier towards occupied space and if adding to existing insulation use non barrier materials...

    For attics IMO the more insulation the better, I come home and the snow is off all my neighbors roofs, but mine is barely melted, that means me energy is staying in my house... When I built this house, I went VERY tight, walls are all 2x8 and 2x6, with as much insulation as humanly possible, the tightest doors and windows, we even have draft tight insulated receptacle boxes, but I have a heat recovery ventilation unit to take care of the "stale air" issues...
  • RobG
    RobG Member Posts: 1,850
    Ghost in the machine

    I am posting this at 3:50 pm e.s.t. and Heat-Pro and BillW somehow posted hours ahead of the actual time? I must be going crazy?

  • BillW
    BillW Member Posts: 198
    edited May 2013
    This thread started in March.

    I answered this post back in March, and Heatpro responded sometime later in April.  May be a computer glitch.
This discussion has been closed.