correct way to fasten metal roofing with screws

Guest User
I'm sure this has been discussed in here before, but don't the nails for tin go on the ridges (tops of V's) and not on the bottoms of the metal roofing as a distributer recently told me? This same person also sold me 750 screws to put on 7 sheets of 20' long 3' wide metal roofing. Maybe I'm wrong, but it seems a disaster in the making to put screws in the flat part of the metal where all the water travels. I did put the screws as he instructed (took less than one half bag of 250)but after putting the screws in I still siliconed around each one. I've never heard of putting screws on like he suggested and wondering if he's wrong? If so, then someone should let him know because he's instructing everyone that buys from him to put them on that way which would be fine until the screw loosens up or the rubber washer wears out. Then you're going to have a seriously leaking roof? As I read on one other site, it would look like putting all your metal in one even stack and then drilling holes in the ridges where you want the screws to go would be the way to go. Is that wrong? Looks like it worked great for all the old 100 year old barns in our area that still are standing perfectly fine??
Ken Buchinger
NCI Building Systems, Inc.
If you are using nails, you would certainly want to put them in the top of the Vs, as they do not seal perfectly to the metal. Screws, on the other hand, are designed to provide a complete seal to the metal. In the metal building world, most all through-fastened panels are attached in the flat and when properly installed, do not leak. I have two metal buildings that are both over 30 years old that still do not leak. That being said, in Florida and South Georgia, pretty much everyone puts screws in the top of the V. I have never reccomeneded doing this because I have 100% faith in screws being installed in the flat, which is much easier thatn putting them in the top of the V.
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