Galavanised or stainless?

is there a reaction when using galvanised shingle nails into treated plywood?

Stainless are very expensive, is it necessary?

If you are nailing shingles to it you probably don’t need treated plywood.
Use hot dipped galvanized nails, not electro galvanized.

Thanks, I am aware i dont have to use treated plywood but you should try telling that to the New Pymouth council!!!

New Zealand housing and building code states that the use of untreated plywood is fine, unless it is a scillion roof.

i have a feelin downunder is going to supprise
us alot in the future.

gweedo.

what is scillion?

Oh and I don’t think stainless is neccesary. Treated wood here now has lots of copper in it, which makes it ultra corrosive. However, it is only corrosive in an electrolyte, such as water. Obviously if your roof goes on correctly there should be no water where the nail hits plywood. That being said I would still use hot dipped nails.

scillion roof> enclosed, pitched ceiling, no attick.

People in NZ have this fear of using untreated plywood on there roof, hence why my local council wants me to use treated.

Thanks for the advice

Gweedo, surprise!!

I take it they use treated for termites?

Not for termites. Un-educated councils who think they know it all is the reason, its so frustrating.

H3 CCA Copper Chromate Arsenic treated plywood and lumber will react and corrode galvanised nails. Same with flashings, never use galvanised drip flashings unless you put them OVER your underlay, or put a seperation layer between the metal and the plywood.
Same with Zincalume, but not so quickly.
I have seen Canadian galvanised drip flashings corrode within 1 year here in NZ just from the metal sitting on the plywood caused by sweating out of the ply. NZ Ply comes from the factory with 18%+ moisture.

Having said that, you couldn’t get SS strip nails here until a few years ago, and we used the galv. ones from Sifco, haven’t had any shingles fall off yet. :wink:

[quote=“MikeNZ”]H3 CCA Copper Chromate Arsenic treated plywood and lumber will react and corrode galvanised nails. Same with flashings, never use galvanised drip flashings unless you put them OVER your underlay, or put a seperation layer between the metal and the plywood.
Same with Zincalume, but not so quickly.
I have seen Canadian galvanised drip flashings corrode within 1 year here in NZ just from the metal sitting on the plywood caused by sweating out of the ply. NZ Ply comes from the factory with 18%+ moisture.

Having said that, you couldn’t get SS strip nails here until a few years ago, and we used the galv. ones from Sifco, haven’t had any shingles fall off yet. :wink:[/quote]

Kiora Mike :smiley:
Thanks for the advice. Because i more than often use treated plywood, for me i have been schooled to think you have to use stainless steel coil nails. The thing is, my competiter use’s galv with treated plywood which is about 700 bucks cheaper for them. But in saying that, every one including myself use galv fixings for the plywood? So im still not a 100% ? all my nails are from sifco.

cheers