This design is a lot stronger and more robust way of making a steel shed.
Welded purlin shed roof.
In a structural steel shed the main portal frames and roof rafters are made from strong steel sections which are welded together and later bolted together.
Snap a chalk line horizontally across the roof two feet down from the top.
Insert two equally spaced nails into the rafter.
Fasten the purlin with 16d common nails into each vertical rafter.
Bycajun welderdate05 03 2009 02 10 i welded my purlins 4 16ga and i used sa 200 6011 1 8 second gear 40 45 and it worked well.
Lay the first purlin at the ridge of the roof down to the chalk line beginning at either corner.
The purlin and the sheeting are weaker inside outside than they are up and down in this configuration.
If your puttin up steel buildings its likely your charging by the square foot don t grind nothing use 1 8 5p or 5p setting depends on your travel speed i run hot and fast to get it done.
Purlins are usually connected to the main portal frame with cleats.
The cleats and purlins holes or punching are generally done to the aisc standardised structural connections with most fabricators manufacturers working within the standards.
With the purlins welded to the face of the pipe the strength of the purlin duplicates the strength provided by the metal sheeting.