ot fastening metal roofing

i have some never used but 3o year old galvinize metal tin 8"long x 2"wide roofing i plan to put on a over hang .. i"ve got may strips at 2" spacing, i"m covering 38" linear,,, i"m also planning to put 6mil plastic under it... My question is do i use nails or the new type screws to hold it down & how many per sheet, do i need them every 2" or top & bottom & center( 3 per sheet across) ( 12 per sheet or is 9 ok)???
maybe i should go look at an old barn or shed?
i"m anchoring in yellow poplar stips w/ a south exposure...

Are you sure it's 2 feet wide and not 3 feet? If it is 2 feet,I'd go 3 across on every 2 foot center firring strip.I also wouldn't put plastic under it.It will sweat like crazy and eventually rot your wood and metal roofing.For fasteners,I'd use self-tapping metal roofing screws that have rubber washers.

' 12" " 1"

I agree with the screws and rubber washers. Seem to leak less than nails with either rubber or lead seal.

We figure 1 SCREW per sq ft. all said and done. Always every nail perloin, and on the bottom of the roof we go on each side of the rib, and every lap on the top of the lap. All intermediate gets one on the back side of every lap ..in the flat about 1/2 inch from the lap joint. Then in addition we put one in every lap. These are the places the wind gets the first wiggle. Then of course behind every rib we place a screw.

We have'nt used neow nails for twenty years plus. I do have some you can have if you so choose.

We get lots of chances to redo metal roofs that our competition has just done. Of course they think that their project should be first in line, as more will blow off if I don't get their right away. We also hear coments like we sure arn't getting them back cause they charge from the time they leave ....till the time they get back, and you live right here an all. Yea, you guessed it ...we go and do it anyway as soon as we can, and often don't charge them because they got screwed pretty bad the first time.

Do it right ther first time so ya don't have to deal with it again.

If you are troubled trying to get the so called ...aggressive screws started through the metal, you may want to rent a Pasload lp fired finish nailer and punch the holes. Just don't put any finish nails in it and dry fire it...probably best use a chalk line. No it will not hurt the nail gun.

Use a 1/4" nut runner of good quality. not the two dozen for 10 cents ones. The better ones have a magnet in the nut runner socket. Keep all metal shavings out of your socket, and often you need to recess the magnet by smacking a screw head into the socket with a hammer to recess the magnet a little more. do it on the new one right away.

Walk ONLY ON THE NAIL PERLOINS unless you weigh less than twenty pounds.

We also use a 2 x 6 on the top and bottom, on top it is advantage for ridge cap, bottom is good for over the roof eve spout hangers.

I don't understand the plastic, and never heard of that one before. I can't think of any reason you would ever need it.

I know you did'nt ask for all this, but I thought it might be helpful.

Here's what little I know. You didn't say if it was a house or other structure. I'm about to do the same thing so I've been studying some.
The screws should be for wood not metal. Metal screws have a smaller thread so they'll pull out of wood. You should use wood screws w/ the sealing washer specifically for attaching metal to wood. You could use self tapping or predrill.
Don't know about the plastic other than it might be unsafe for working on.
What metal buildings do is sweat. It's if there are different temperatures inside and out. If you are doing a house the temperature will be different. It's not water from the out side it's accumulated moister from inside. Insulating will stop the moister. My metal barn doesn't rain because it's the same temp inside and out. I know a guy who runs a bunch of goats and sheep through his and says it constantly rains in there because of all the animal heat.

hey guys, i'm sorry about the size , its 2 foot by 8 foot,,, its a kentucky stye porch overhang, the plastic was to keep it from dripping during a temperature varation like my one shed does.. no livestock, but every now in then , mostly in the winter on warm days it drips (rain) in the shed.

sounds like i need to use the screws , poss, every 6 inches along the bottom, every 1 foot elsewhere, this is the old stye roofing with no flat area , all wave thanks too all, this site has been a life saver for me, my naa ford had a rear seal go out last summer, a big help,, then just a month ago i posted a note on the fuel filter for a dodge van, someone posted a picture the really helped, it was up under the fuel tank.

Wood screws will hold better and I would use screws that won't rust. Since they've used screws in drywall you never get any nail pops. Hal

There are special screws for steel roofing. You can get them at Menard's or Home Depot type stores. The box is labeled "for use with steel roof on wood framing" or something like that. They are 1/4" drive zinc-plated screws with washers. They come in a variety of colors to match your roof finish including galvanized color. Don't use nails, they always work themselves out and you risk hitting the steel with a hammer.

I have used the special rinkshank nails with rubber washers on sidewall steel with good success, except I always put screws on the bottom and top rows. The nails are a lot cheaper than the screws.

I would not use nails anywhere on a roof though. Only the self tapping screws (with the rubber washers) designed for this use should be used on a steel roof.

Got metal roof and installer was pretty careful about torque on screws with washers. He had each man check tool for proper torque on test stand.