5v over foam purlins?

I am getting ready to have installed a metal roof. My contractor wants to put foam purlins down over my existing shingle roof, then the metal over that. I am calling them purlins, but not sure if that is correct in this instance. Foam furring strips? Will that work? Is it correct, and do I need overlayment over the existing shingles?		clay Ferriola 4/17/2016	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/21139/find/
I personally have not heard of anything other than wood battens. By all means I would make sure that the manufacturer of the roofing approves this procedure. And, yes, I would put down underlayment.		Todd Miller Isaiah Industries, Inc. 4/17/2016	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/21140/find/
I have not heard of a foam batten but have seen a rolled (plastic type) furring strip. This may be to what the contractor is referring. I agree with Todd, either way, use the underlayment.		Lynn Noesser 4/20/2016	Share Or copy this URL: https://www.metalroofing.com/spirit/comment/21141/find/

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