What is the best roofing screw?

[georgebriansky]

Hello. A lot of the roofing screws I have on a metal corrugated roof are rusty. What would be a good lasting screw to use? Some have a rubber washer, do these last? Thank you

[JacobZ]

Hi @georgebriansky,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

The only screws you should be using for metal roofing are galvanised hex head screws with a seal.

If the framing beneath the metal sheets is timber, use these Zenith 12 - 11 x 50mm Galvanised Hex Head With Seal Timber Screws.

If the framing beneath the metal sheets is metal, use these Buildex 12-14 x 50mm Climaseal Hex Head Hi-Grip With Seal Roofing Tek Screws.

If you've searched for roofing screws, you might have seen screws with a dome washer like these Otter Polycarbonate Roofing Screws or these Suntuf Clearfix Roofing Screws. Do not use these screws. They are designed for polycarbonate roofing, which requires an expansion gap in the material around the shaft of the screws. The dome washer is wider, so it can cover this expansion gap. They would work to some degree, but the screws I mentioned above will seal the hole in the metal roofing far better than these will.

When installing your screws, tighten them so the washer compresses, but don't overtighten them. If the washer splits, which it will if it is overtightened, then the seal is broken, and water will be able to find its way in. Just tight enough to compress the washer is what you are looking for.

Let me know if you have any further questions.

Jacob 

[georgebriansky]

Hello and thank you for the information. Your suggestion seems good.

Do you know much about the durability of the seal. I assume they are rubber so do they last OK out in the weather? I have seen Bridgland screws with Aluminum seals but I assume they are not suitable for a corrugated roof.

Thanks again

George

[JacobZ]

Hi @georgebriansky,

I can't say I have personal experience of their lifetime, but most sources I have found say the rubber seals will typically last between 15-20 years if they are installed correctly.

I have never seen a screw with an aluminium seal, but it wouldn't be advisable, as when dissimilar metals, like aluminium and steel, are in contact with each other, they will corrode prematurely because of a phenomenon known as galvanic corrosion.

The standard screws for roofing are galvanised steel hex head screws with a rubber seal. It would be best to use these screws.

Let me know if you have any further questions.

Jacob

[georgebriansky]

I really appreciate your advice. The roofer recommends screws that have a Cyclone Assembly, appears probably to cushion the effect of a cyclone. Seems an overkill to me but your opinion would be welcome.

Thanks again

George.

[JacobZ]

Hi @georgebriansky,

I suppose it depends on if you are in a cyclone-prone area. 

Considering your roofer has recommended them and they are aware of the conditions in your area, they are probably worthwhile.

I can't say I'd heard of them before, but our supplier Bremick does make them. You can see an example here - Bremick 14G x 50mm B8 Hex Head Cyclone Roof Screw.

If you check out their Cyclonic Re-Roofing Brochure, you will see there is a screw for almost all situations. We will be able to special order the correct screws for you through your local store's Special Orders desk. You will just have to advise them of the specific type and colour so they can get in touch with Bremick to get a price and then order them.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

[Noyade]

I just used traditional Tek screws (wooden battens) - the rubber seals have held up well after 15 years.

[georgebriansky]

The owner has decided to go with the Cyclone screws so I will do that.

I really appreciate your advice and help. thank you.

Just by the way, Bunnings charge $309 for a 250 box, that's well over a dollar per screw. Seems a bit high? Maybe a mistake as another hardware store sells these at $105.21 for a 250 box., $200 less. Maybe worth checking.

Once again, thank you very much for all your advice.

George

[MitchellMc]

Hi @georgebriansky,

Thanks for the heads-up, we'll certainly pass it on to our pricing team to look into.

Mitchell