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

[Krome10]

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

 

[bourbon]

Yes, you are overthinking it.

 

[worn thumbs]

Hot dipped every time,they have a much better coating.The flash plated zinc will be a few molecules thick at best.

 

[Jake]

Hot dipped is way better than electrolytically deposited if that is what you mean by coated.

 

[Spectric]

You could use stainless screws or these Fastco Fasteners & Fixings

if you want better corrosion resistance then look at the A4 Spax

https://www.spax.com/gb-en/c/screws/decking-screws.html

 

[pgrbff]

copper

 

[Fergie 307]

You can also buy stainless nails, but dipped are perfectly adequate. Problem with plated ones is that the coating is so thin it's likely to get damaged just by the act of hammering them in, then they will rust. The hot dipped ones have a much thicker coating.

 

[Krome10]

Many thanks for the helpful replies...

Yes, you are overthinking it.

I do have a tendency to! But interesting how other responses say that hot dipped are far superior, so I'm glad I asked. It does leave me wondering though... If hot dipped are so much better, why do people choose to use (and roofing stores choose to sell) the far inferior electro zinc coated? Samac were very quick to assure that they were perfectly fine for fixing battens. They don't even make hot dipped nails...

RE: copper, I'm using copper clout nails for the slates themselves but don't think it is necessary for the battens from what I've read.

Ta

 

[Sideways]

The same applies to unistrut (electrician's meccano).
Post galv (dipped) is dearer and better than Pre galv (electrolytic).
Dipped has a far far thicker coating and lasts way longer.
The bright zinc finishes applied to most cheap screws and even things like the metal latches on dewalt tool boxes is very thin and barely lasts a year in a damp environment.
Dipped or stainless is the way to go.

 

[pgrbff]

I think we used copper for battens as well but it was a long time ago.

 

[amakah]

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

Hello, I live on the Shetland isles and due to the weather/salt air all our outside building is done using stainless steel nails. All the builders merchants here keep a huge range of sizes.

 

[woodspiral]

I don't think you are overthinking this at all. Careful choice of the right materials can make the difference between a success and a disaster. I am thinking specifically of a couple of things which have grabbed headlines recently.

On the home front, the roofer who attached the pantiles on my garage used mild steel nails and they are expanding and are slowly cracking all the tiles. It's like watching a disaster movie in timelapse. One roofer I had to come and look at it said he's always been told this is the reason never to use steel nails for fixing tiles but he's never actually seen the mistake for real before. The brickwork on the garage is excellent.

For fixing cast iron guttering to the fascia I used stainless steel screws to guard against this kind of expansion since cast iron will crack too. If expansion due to rust is not a concern, in wood etc, and the fixings are out of direct weather then I would have thought zinc coated is fine. I'm glad you are using copper nails for the tiles.

 

[Phil Pascoe]

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?

 

[Krome10]

Thanks for all the great replies and help, some really interesting stuff to consider. I'll definitely use hot dipped for the battens, and you've given me food for thought as to what to use elsewhere.

With regards SS screws, I don't want to complicate things but are there different grades? Or are all SS screws made equal?

Cheers

 

[Phil Pascoe]

A2 is usual, A4 is marine iirc.

 

[Sideways]

Yeah. A4 is more stain / corrosion resistant so the choice when exposed to salt.
Common A2 is fine for most purposes.
Stainless fixings are softer than normal screws and less strong. If you are used to power driving screws especially the self drilling variety you will find stainless shear much more easily. Drill pilot holes and go easy while you get used to them.

 

[ChaiLatte]

If steel nails' expansion cracks the tiles, surely copper ones would as well?

I think you are correct in that it is the rust that causes the expansion rather than any heat effects.

Iron oxide is less dense than iron, so occupies a larger volume.

The nails would have to be a fairly tight fit in the holes in the tiles for this to be a problem. I wonder if they have been driven in too far, then rusted and there is not enough 'give' in that direction to accomodate thermal and humidity movements.

 

[whereistheceilidh]

Suggest you do not use Stainless with cast iron unless you sleeve it. Cast will rust more quickly, especially near the sea. Electrolysis.
Also suggest against copper nails in exposed conditions with heavy slates. The movement of the slates wears them. Did a re-roofing job where heavy Ballachulish slates halved the thickness of copper slate nails. Hot dipped galvanised every time.

 

[Krome10]

Also suggest against copper nails in exposed conditions with heavy slates. The movement of the slates wears them. Did a re-roofing job where heavy Ballachulish slates halved the thickness of copper slate nails. Hot dipped galvanised every time.

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?

 

[Jameshow]

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?

Maybe the wind has something to do with it?