Somewhere in the installation manuals for the steel roofing I read that you need to attach the 2x4 purlins to the framing with 60 D - 6 inch long, ring shanked nails. Well this desk jockeys arm is not up to hammering hundreds of these nails in Soooo.

We picked up a used hand or palm nailer on eBay. Its kind of like a mini pile driver, you put the nail in the nose and when you push down on the body of the tool it starts to pound the nail in. It worked REALLY slick and we got all of the purlins installed

And somebody is asking, why do you need 6 inches nails for?? Well the 2x4 purlings are actually 1 1/2 inches thick, the existing roof boards are 3/4 inch, so you have 2 1/4 inches of lumber even before you get to a rafter. A standard 16D nail is 3 1/4 inches long and so you're only getting 1 inch of nail into the rafters.

Also there is the issue of wind uplift forces. With purlins spaced 2 foot apart vertically and the rafters being 2 foot apart (horizontally) each two nails (holding the purlin to the rafter) must be able to in effect hold down 4 square foot of roofing. One document talked about 90 pounds of wind up lift force possible per 1 square foot of roofing. And two nails are supposed to handle 4 square foot, or 360 pounds of force. I KNOW a 16 penny nail will not hold that. So, 60 D nails are a must, unless you want your entire new roof blowing off, purlins and all when a strong wind comes along.