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Community and Q&A

Insulated vinyl siding over Comfort Board 80?

cragged | Posted in Green Building Techniques on

What do you think of installing insulated vinyl over comfort board 80? Is there a particular product that would work best for this? This would be done directly against the comfort board with no battens in between.

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  1. JC72 | | #1

    That answer is ultimately left up to the manufacturer of the vinyl siding since they carry the warranty but it seems possible depending on the thickness of the Roxul. However I can't see how there would be any insulating effect gained from using insulated vinyl since vinyl is inherently leaky. Why not just use uninsulated vinyl?

  2. GBA Editor
    Martin Holladay | | #2

    Vinyl siding manufacturers tend to be very conservative in their recommendations concerning the required substrate. So I'm guessing that your hurdle will be that you are unlikely to find a vinyl siding manufacturer that is willing to approve that type of installation.

    Of course, if you are willing to ignore manufacturer's installation instructions (giving up on any possible warranty), you can do whatever you want.

  3. cragged | | #3

    This is Craig again. I posted the initial question. Would uninsulated vinyl work over 2" comfort board? What would the best fasteners be?

  4. GBA Editor
    Martin Holladay | | #4

    Q. "Would uninsulated vinyl work over 2 inch Comfort Board?"

    A. I'll give the same answer as before. Probably not -- but you need to check with the vinyl siding manufacturer, unless you are willing to give up on the siding warranty.

    If you think you would be satisfied with just R-5 of continuous exterior insulation, you might want to check out a product called DuPont Tyvek ThermaWrap R5.0. I don't know if DuPont is still promoting this product. It's a little odd. It's possible that the product bombed and was withdrawn from the market.

    Here is a link to a GBA story about DuPont Tyvek ThermaWrap R5.0: Two New Exterior Insulation Products for Walls.

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