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?
http://www.thermacork.com/external-walls
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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.
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.
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.
Smoky.
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.
Alan,
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?
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 (https://www.smallplanetsupply.com/s/RDH-THermaCork-Report-hkf6.pdf). 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).
Alan,
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%).
https://www.buildingscience.com/documents/insights/bsi-038-mind-the-gap-eh
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.
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.
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.
Peter,
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.
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.
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 (https://www.youtube.com/watch?v=Nb3AlSNXWQM).
I did find an informative GBA article dated 2013 about installing ThermaCork. A lower density ThermaCork was used under strapping and cladding. (https://www.greenbuildingadvisor.com/article/installing-cork-insulation)
This is the latest installation instructions as of September, 2021.
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.
Anyone have experience using the high-density acoustic thermacork panel in a flooring system? Im looking for something to reduce sound from the second floor over a ceiling with exposed timbers.
I’m wondering if the high density stuff would hold up as a finish flooring.
Adam
Adam,
Cork on its own is not strong enough for flooring. To make the product they have to add resins and hardeners. I doubt the high density insulation has adequate amounts of these to resist the forces exerted on flooring.
That’s what I thought too. The sales guy I talked to at small planet supply thought the standard grade would hold up fine, so I imagine he’s just trying to sell some cork.
I’m worried that any flooring product would be too thin (1/2” or so?) to do much for the acoustics.
Adam,
There are a lot of effective purpose-made acoustical underlayments, which leave you free to use a wide variety of finished flooring. That's the direction I'd go, rather than trying to combine the two functions.