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Community and Q&A

ThermaCork Facade, too good to be true?

alanferg | Posted in Green Products and Materials on

Does anyone have experience or insight into using ThermaCork Facade? I’ve only found one article and one Q&A on GBA briefly referencing ThermaCork insulation.

ThermaCork Facade can be fastened directly to sheathing. I could replace all three components of my exterior wall assembly (4″ GPS foam, vertical strapping, cladding) with 4″ or 5″ of ThermaCork Facade panels.

Aside from the plain appearance, is this product too good to be true?

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  1. Expert Member
    NICK KEENAN | | #1

    I've used it. I don't have experience with long-term durability. It's brittle and even in a short time the corners tend to get dinged up.

    It's very expensive, both for the material and to install. As I recall the only acceptable fastening method is about 12 stainless finishing screws per panel. They specifically say you can't nail it. I did 2" panels and used 3" screws, which were a significant expense. You'd have to use 5" screws, I don't know if they even exist.

    1. Expert Member
      NICK KEENAN | | #2

      On the plus side it does look good and is pleasant to work with. It does serve as both insulation and cladding. It is more vapor open than foam.

      1. Adam_F | | #3

        I have some samples of this stuff, as it was something I am/was considering. Can't help but notice the smoky aroma.

        I can only wonder how it smells being trimmed.

        1. Expert Member
          NICK KEENAN | | #4


    2. alanferg | | #5

      Did the corners get dinged from handling and installation? I've yet to calculate the cost difference of ThermaCork vs my planned wall assembly, but I'm curious if it's cheaper.

  2. Expert Member


    It sounds like an interesting product. While it does allow you to eliminate the strapping necessary for thick foam, you then don't get the benefit of a rain-screen cavity. I don't know much about cork. Is it a reservoir cladding that needs a gap behind to stop water moving into the wall system?

    1. alanferg | | #7

      Malcolm, I've been wondering myself if a drainage plane between ThermaCork Facade and sheathing is applicable. My understanding of a rain-screen is to ventilate and allow drainage of moisture that gets behind cladding. In this case, ThermaCork Facade is an all-in-one product (exterior insulation and cladding). With ThermaCork Facade, my concern is moisture that does find its way in from the outside or vapor from the interior getting trapped between the ThermaCork and sheathing. I found this study by RDH Building Science and Small Planet Supply evaluating ThermaCork insulation over several years, but, it seems they still used a rain-screen and cladding over the ThermaCork ( The report is quite technical for me so I'm still trying to understand what I'm reading. If a rain-screen is applied between the ThermaCork Facade and sheathing, how does that affect the sheathing in cold temperatures? It seems to me the cold air would negate the insulative ability of the ThermaCork and move the dewpoint into the stud assembly where we don't want it. Perhaps a thicker housewrap designed for drainage can be used between the ThermaCork Facade and sheathing (I know the products exist, can't think of its name off the top of my head).

      1. Expert Member
        MALCOLM TAYLOR | | #8


        The details with it used as a cladding show a direct attachment to a solid substrate. It may need that for rigidity, but maybe a shallow cavity using either a dimpled WRB or mesh would work. Fortunately small cavities behind exterior rigid insulation don't reduce the R-value much. Building Science said a 1/8" gap had a negligible affect (5%).

  3. Expert Member
    PETER G ENGLE PE | | #9

    A housewrap like Hydrogap would be appropriate for a system like this and would have little effect on insulation performance. Then again, the manufacturer recommends Prosoco's fluid-applied WRB and that would also be an excellent choice. There's probably enough roughness to your sheathing to provide enough drainage behind the cork.

    I see on their website that the panels have a shiplap edge. This provides for fastening with 2" screws to the substrate at the edge at least. I think they intend the rest of the panel to be fastened with adhesive, but that's not shown. Certainly, just hanging it from one edge would not be sufficient.

    In my experience, cork is a somewhat odd material in terms of durability. It is naturally rot resistant, but will rot in the right conditions. The right conditions mean it is exposed to enough moisture at the right temperature, like everything else organic. I'm not sure I would trust it on a warm/wet wooded site, but out in the open or in the desert it might last forever.

    It does produce a rather unusual visual effect. If that goes well with your design, that's fine but you should be prepared for the significant panel-to-panel color variation.

    1. Expert Member
      NICK KEENAN | | #10

      When I installed it the supplier was very specific that it had to attached with screws -- not nails -- through the face. If I recall it was a 4-wide by 3-high pattern per panel. And at least one row per panel had to penetrate the sheathing into a stud.

      1. Expert Member
        PETER G ENGLE PE | | #11

        Yeah, that's a lotta fasteners. Their website is not at all specific on fastening requirements, but they do have an all-adhesive system for use over masonry, so I suspect that it could also be done over a fluid-applied WRB. An arch./engineer would have to sign off on it though.

        1. Expert Member
          MALCOLM TAYLOR | | #12


          When used as a cladding the website says:

          "Glued fixation (adhesive) of ThermaCork Facade boards directly to support using Secil Lime Plaster."

          Which would complicate any air-space.

          1. Expert Member
            PETER G ENGLE PE | | #15

            I did see that. I'm not familiar with that particular plaster, especially used as an adhesive, so the rest is speculation. I know the EIFS folks use adhesive to attach the foam layers using a notched trowel and vertical ribbons to create a narrow drainage system right in the adhesive layer. I would expect the same can be done for this plaster. Or, an organic adhesive may be substituted for the plaster, though lime plasters are generally very environmentally friendly. Still, as a new material and even with manufacturer's blessing, there's going to be a steep learning curve.

    2. alanferg | | #13

      My new build is in climate zone 7, bitter cold dry winters (-32 this morning) and warm humid summers (muggy 70s and 80s). The build is on top of a small hill surrounded by woods on three sides. I've wondered about rot resistance in our summer climate.

      Yes, it seems Facade ThermaCork is recommended installed over Prosoco Cat 5 with screws on a stud/sheathing assembly, according to website and a Small Planet Supply video (

      I did find an informative GBA article dated 2013 about installing ThermaCork. A lower density ThermaCork was used under strapping and cladding. (

  4. Expert Member
    NICK KEENAN | | #14

    This is the latest installation instructions as of September, 2021.

    1. Expert Member
      PETER G ENGLE PE | | #16

      That's helpful. The PL Premium approach would get rid of the fasteners, but you're going to use a lot of adhesive and that might be as expensive as SS fasteners.

      I do like the footnote about woodpeckers. They can be a real pain if they decide they like a building.

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