Metal roof over Zip panels

[Arky217]

Has anyone used Zip panels on their roof and then installed metal roofing ?

I'm about to install standing seam metal roofing on the Zip panels on my roof. At first, I was going to install the roofing directly over the Zip panels as per Huber's (Zip manuf.) suggestion, since the panels already have the Zip weatherproof membrane bonded on the surface.

Later on, I got to thinking that I would first put down a synthetic underlayment (Grace Tri-flex) just for extra protection.

After thinking more about it, however, I now wonder if maybe the underlayment is not only not necessary but that I would be better off not putting hundreds of more holes through the Zip panels with the cap nails for the underlayment.

Now I'm back to thinking that I should just put the metal directly over the Zip panels.

The Zip panels have been on for about 5 months already and so far have been watertight.

Anyone have any thoughts about it ?

Thanks,
Arky

[rich2Vermont]

I'm hoping to get a standing seam on our zip panel roof in the next couple of weeks. Months ago, when I was calling around to get an idea of cost, more than one roofer mentioned putting down an ice and water shield membrane. I was kind of surprised as I thought that one reason for the cost of a metal roof was that it was a very long-lasting, integrated system, one not needing any extra protection. But, given that it would be difficult and expensive to fix any leaks after it's roofed, it may be better for peace of mind alone to put down a membrane. I'll be talking again with the roofer this week. I'll let you know what he has to say on the matter.

-Rich

[rmcewen]

FWIW, I installed my steel roofing directly over the zip panels using purlins.

One snowy winter and rainy summer and no leaks so far.

[Alan Gage]

Came across this when searching for something unrelated and thought it might interest you:

http://forums.jlconline.com/forums/showthread.php?t=42047&highlight=metal+roof+venting

Alan

[DirtyLittleSecret]

I had the same internal controversy when I did mine a few years back.  Finally decided that since both Hardie and my metal roof manufacturer both recommended direct application that it was the way to go.  Havent had any issues since, and sits tight.