Building a 10’x26’ deck with metal r panel roof. If I use 12’ rafters how much over hang can I let them hang off the header? Also how often should I put a row of screws in the r panel? Thanks

You talking how much eave? You're wanting a 2' eave past the header at 10'?

0, 3', 6', 9', 12' Is where your purlins (wood) should be.

You can try
0, 4', 8', 12' depending on how much pitch you have.

I recommend PBR panel. And a screw goes right beside every rib.

So would you put a screw on each side of the rib? Also how far apart? I’ve seen every 1 -2’ a row of screws

You can take this to the bank. He has been there and done that.

No, just one side. Look at Mueller's recommended screw placement. Their pics are faster than me explaining it.

Thank you

I don’t believe in more than a 6” overhang.
Lathes no more than 5’ OC , or at 4’ in this case.
Screws on each side of the high rib at eaves, 12” spacing in the field.
Lap screws on 20” centers.

If your asking how far your rafters can extend past your beam, that depends on rafter size and depth of seat cut and also if you are going to have a band tying all the rafters together. If your asking how far your metal can extend past your last lathe board if you are using 26ga R-panel you can go easily 12" without bending problems as long as there is no chance of a heavy snow load.