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

[whereistheceilidh]

That's interesting and contrary to everything I've read... The usual spin on things is that the movement of the slates wheres off the galvanisation and creates a weak point on the nail, which corrodes and leads to slipped slates etc. But not in your experience?

Not with good quality hot dipped Krome. BZP deffinitely. The wisdom I was always told by old non-yachty boatbuilders is that the galv acts to wear with the steel/iron. Certaily the good old Galv nails lasted better than copper on a heavy exposed roof....can only say what my relatively limited experience is.

 

[woodspiral]

If steel nails' expansion cracks the tiles, surely copper ones would as well? It expands more than steel. Or is it the rust that causes it?

I was referring to the expansion of the nail due to oxidation aka rust. Expansion due to heat would be negligible in comparison and not a concern in this situation.