fiber cement siding over rigid foam shea

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Replies
Short answer,....yes you need the furring.
F/C siding can be installed over rigid foam up to 1" according to Hardie. Over that,... weight and gravity combine to bend the fastners or pull them out.
My intent is to nail through the cement board siding, through the 2" of foam and into studs. I am looking at about 3 1/4 to 3 1/2 in hot dipped galv nails. The question then becomes am I asking for moisture problems if I don't use the furring strips.
Around here, the conventional wisdom is that normal fasteners are not adequate to this task, as they will eventually bend or sag. Special strengthened screws are used.
If you are using Hardie fiber cement siding, you are going over the 1" limit that Hardie places on their product over rigid foam.
http://www.jameshardie.com/pdf/install/install_plank_north.pdf
I haven't read the Certainteed installation in some time, but I believe it to be the same.
As far as the moisture problem I don't think that would be an issue if the foam board is taped and otherwise flashed correctly. There are several how to install f/c siding sites on the web. Just google fiber cement siding installation.
The devil is in the detail, and no matter how good a product is, it will not overcome a improper installation. You also run the risk of negating any manufacturers warranty by installing it outside their parameters.
"The question then becomes am I asking for moisture problems if I don't use the furring strips."no, if you detail the insulation well, moisture is not the concern. The concern is that the nails may not hold up the weight of the siding at 2" suspension, and could bend over time, leading to a sloppy appearance, or at worst a catastrophic failure with human injury.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
And wavy siding...
what I meant by sloppysun up there yet?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I was just finishing up some slate as dawn was breaking. It was fully unrepairable by the time the drillers showed up two hours later.Hell, we can sleep when we're dead, eh?
I figure to spend some time singing and dancing when I die - no more pain so I can dance - and it won't hurt the ears of anyone close by when I sing!;)Rest of the time I'll be in heaven's library
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!