Which aluminum railing orientation is stronger?

[drakejest]

I am wondering which orientation of the aluminum railings gives the stronger result should i go along with the Purlins (Red Line) of the roof or across multiple purlins (Green Line) ?

 

[timselectric]

Either way should be fine. The purlins already spread the weight across the joists.
Just go with whichever works best (easiest) for your layout.

 

[drakejest]

Either way should be fine. The purlins already spread the weight across the joists.
Just go with whichever works best (easiest) for your layout.

Got it, how about in terms of "lifting resistance" during typhoons?

 

[fatjay]

Got it, how about in terms of "lifting resistance" during typhoons?

Personally I would go horizontal. You're tying the rafters together with a stronger material. But with the panels being against the roof it should not be much wind getting under there to lift. I would imagine you could install a wind guard to deflect it as well if it's a concern.

 

[Osmethne]

Go for the rafters, or trusses in modern roofs. Much stronger than the purlins.

 

[fatjay]

Go for the rafters, or trusses in modern roofs. Much stronger than the purlins.

Problem is the purlins sit on the trusses, so there's a gap between the metal roof and the trusses, so you can't clamp down to the trusses without damaging the metal roof.

 

[Bongbong]

If you're concerned about typhoons, securing the panels to the rafters would likely be the more reliable option. However, I do recommend double-checking how well the rafters are anchored to the foundation to ensure the roof doesn’t lift during strong winds. At the same time you might want to verify that the rafters can support the weight of the panels to avoid any structural issues.

 

[1234enough]

Do the purlin spacings suit the panel spacings, if installed horizontally ?
If not may be better to go vertical.
Also need to ensure fixings into purlins are suitable and robust for any given loadings ( load being down or lift).

 

[timselectric]

Got it, how about in terms of "lifting resistance" during typhoons?

That's going to depend on the attachment hardware.
Orientation doesn't matter for lift resistance.
You are attaching to the purlins, in both orientations.