Hot Dipped vs Zinc Coated Galvanised Nails - which for roofing?

[Oxbow16]

I'm not sure if I'm overthinking this...  

 

I was under the impression hot dipped galvanised is far superior, and best for any outdoor use...  

 

I need to do some roof repairs and bought a pack of round wire nails made by Samac, for fixing sarking boards and battens to rafters.  The Samac nails are sold in several roofing stores so I presumed they were exactly what I need.  But it turns out they are zinc coated.  And one reviewer on Amazon says he used them outdoors and they rusted quickly.  

 

Hoping to get started on that part of the roof tomorrow.  Do I need to go and buy some different nails (if I can find some locally)?  Or go ahead with what I've got?  

 

There doesn't seem to be a price difference between the two, so if hot dipped are better, I'm confused as to why so many roofing stores only sell zinc coated round wire nails?  Is there a downside to hot dipped?  

 

Many thanks      

 

[markc]

Hot dipped zinc coating is better for weather protection but they can be sharp, a bit rough looking.  BZP is bright zinc plated and done by electrolysis so the coating is thinner and more even (and usually shiny) but not as hard wearing.

[Oxbow16]

Interesting then why the roofing shops sell BZP and why it isn't standard to just use the better protected and longer lasting hot dipped.  

 

I should add, that Samac said their nails are "electro galvanised", but later added that they're "mechanically galvanised".  Not sure if that refers to yet another type / category? 

 

They also said that they are Service Class 2.  

 

Cheers