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Adding additional insulation to existing 2×6 framing

user-7005676 | Posted in Energy Efficiency and Durability on

We built our house about 30 years ago when 2×6 framing with plastic vapor barrier inside, 6 inches insulation, 1/2 wafer board, Tyvek house wrap, Cedar lap siding.

We would now like to replace the windows and siding and add additional insulation to the exterior. I have read articles on how much rigid foam we should apply if there was no plastic vapor barrier installed. Also read about rockwool as maybe an option to allow the wall to breath.

Looking for suggestions….thanks!

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  1. user-2310254 | | #1

    Where are you located? And what is your name?

  2. user-7005676 | | #2

    SW Wisconsin, Jeff Hastings...I'm new to this:)

  3. GBA Editor
    Martin Holladay | | #3

    User 700etc,
    1. Here are links to two articles that discuss the question of whether your interior polyethylene is worrisome:

    The Exterior Rigid Foam is Too Thin!

    Rethinking the Rules on Minimum Foam Thickness

    The brief version: The interior polyethylene isn't particularly worrisome.

    2. If you are interested in installing a continuous layer of rigid mineral wool, you might want to read these articles:

    Installing Mineral Wool Insulation Over Exterior Wall Sheathing

    Installing Roxul Mineral Wool on Exterior Walls

    Wrapping an Older House with Rock Wool Insulation

    3. If you decide to install a continuous layer of rigid foam, you might want to read this article:

    How to Install Rigid Foam Sheathing

  4. user-7005676 | | #4

    Excellent, I'll check them out...thanks Martin.

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