Need to hang Hardie plank+airgap on 4″ XPS on plywood. Who supplies fibreglass girts to handle this?
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In the hanging of the Hardie plank I am told to use a Z girt. But I am searching for a more green friendly product that also won’t give a thermal bridge signature as does the Z girt although small.
I have found a supplier who currently only makes a 3.5″ fibreglass girt (Cascade) but need a 4″ to maximize my building envelop performance in my Zone 8 home.
Anyone out there know of such a supplier?
Or alternatively another method of putting this together without thermal bridging and being as green as can be at this time?
Thanks for your help.
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Replies
Perfect timing; I'd love to see responses to your question, as we are planning to install 4" semi-rigid rockwool exterior insulation and are struggling to find a way to install stucco/wood siding over it. Could you please send a link to the Cascade website? Thanks.
I'm currently doing a REMOTE wall with 4" EPS. Using a drainage plane and screwing through into the studs. Not much for the help on the thermal bridging; but with the lath spaced appropriately, it meets Hardie specs..
Since this is new construction and I have open studs - any screws that do not fall on the studs and penetrates the sheathing get spray foamed from the interior before I blow in cellulose in the walls..
If the 3.5" option (with the girt) is better you can get foam cut to any thickness pretty easily - especially in AK.
Li Roz,
That would be Cascadia, the Canadian maker of fiberglass frame windows, and here's a link: http://www.cascadiawindows.com/products/series53.php.
John,
XPS is not a "green" building material because of the very high global warming impact of the blowing gas. It would be preferable to use EPS, polyiso or rockwool insulation. Rockwool adds some complexity because it's not rigid enough to support furring with just screws. 4" thickness of rigid foam plastic (such as polyiso) will not require a Z-girt, just a long screw that embeds into framing. You can get SIP screws long enough for any thickness of insulation you'd want. Here's an example: http://www.mcfeelys.com/product/TMR-4065/14quot-x-6-12quot-Extra-Long-Wafer-Head-Timber-Screws--Spider-Drive.
John,
For more information on the fasteners required to install vertical strapping over foam, see Fastening Furring Strips to a Foam-Sheathed Wall.
you could use something like 'squash blocks' say a fiber glass tube or pvc pipe in a remote wall framing style. the tube/pipe goes between the stud and the vertical batten//furring
the tubes keep you from squashing the vertical batten/furring through the rockwool and should be R friendly and you can choose your custom length. you also get to choose from a varitety of batten types rather than relying on steel girt. i imagine the cascadia fiberglass spacers are pricey
in the article martin references i think there is an example of using 2x3s like studs to hold the rockwool in place, but you will pay a small thermal bridge penalty.