How to stop roof screws rusting?

[Amrad79]

Hi my colorbond roof is 12 years old  . l live 4 km from the coast. Theres no noticable rust on my roof but l noticed about 10%-15%  of the roof screws have some rust on them , All the rest look normal . l think the rust just stated a couple of years ago. l was thinking just replace the rusted screws and treat the remaining screws that are not rusted with some sort of rust inhibitor product or paint to stop them from rusting. Could l do that or should l replace all the screws not just the rusted screws, What is the better option ? and what product to use to prevent the screws from rusting. My concern is if the rust could spread from the screws to the roof, but they have rubber washers under them which would help, how urgent do you think the problem is , could l wait a year to replace them, thanks

[MitchellMc]

Welcome to the Bunnings Workshop community @Amrad79. It's terrific to have you join us, and many thanks for your question about replacing roofing screws.

Are the existing screws powder-coated and painted or just straight galvanised? It sounds like they could just be galvanised steel, so my recommendation would be to pull them out and replace them with powder-coated screws in the same colour as your roofing. This painted coating provides additional protection from the elements and salt water.

Provided the rust is only on the heads it doesn't sound like replacing them is something that needs to be done immediately.

Please let me know if you have any questions.

Mitchell
 

[Amrad79]

thanks, the screws are the same color as the colorbond roof , l dont know if that means they are power coated or galvanized , Do you think because only about 10% of them look to be rusted would it be possible just to have those rusted ones removed and the reamaining  screws painted or treated so they dont rust in the future which might be cheaper then removing them all ? or do all need to be removed .  ls it something plumbers do ? l was also thinking of using a handyman from ' Hire a hubby' is that a job for a handyman or would someone with more special skills be needed from a roofing company .  Would you have any idea of the sort of cost it would be for an average sized house to replace all the screws, l guess it wont be cheap. But as only 10% look to be rusted it must be early stages and do you think l should have alteast a year before l need to do anything

[MitchellMc]

Are you able to share a picture of one of the worst rusted screws, @Amrad79? Bearing in mind that your safety is the top priority. Please don't go onto the roof unless you are confident in doing so. If there is minimal rust on the screw head, just a spot here and there, they might be fine for the next ten years. If they are heavily corroded, they'll need to be replaced before they become so disintegrated that they can't be removed.

I think your best move at this point would be to have a roofing specialist company come in and inspect them. They'll be able to advise on the best course of action and provide an estimate on the work.

Did you have the roof installed? If so, I'd be contacting the installer to see if there is any warranty on the screws that have been used. Typically, if they had a Colorbond coating added, they would have a significant warranty.

Mitchell

[Amrad79]

l have a couple of photos how bad is it  , should l replace soon, The house was built 12 years ago so the roof came with the house and the company went out of busines so l dont know how to contact them to get the warranty. l applied some rannex rustbuster on one of the screws and all the rust totally disappeared, l was thinking if l got someone to apply rannex rust killer on them and then painting over them it could give them a few more years life before replacing

[MitchellMc]

Given how heavily corroded those specific screws are, when others don't even have the beginning signs of corrosion on them, my money is on that there is something wrong with those rusting screws @Amrad79. If they were new screws when installed, then their coatings were not applied correctly by the manufacturer. There's no reason why some screws are not affected at all, and some are extensively corroded. When you have two entirely rusted screws next to one that's unaffected, it tells me something is wrong with the rusted ones. All screws on the roof should be rusting at a similar rate. Let me mention @Dave-1 and @Nailbag for their thoughts.

My advice would be to have the corroded screws replaced. It's not worth risking the roof sheets when you could have someone replace all the corroded screws in a day. I think it would cost you more to have someone treat and paint the screws than replace them. It takes about 20secs per screw to remove them and screw in the new one, whereas it would take several minutes to treat and paint them.

Mitchell

[Amrad79]

thanks , so you think just get the rusted screws replaced and leave the good screws ,or should l get them all replaced,  l was thinking of calling my local plumber but do you think a roofing specialist would be better. also from the photo do you think the roof itself still looks good and non rusted , just the screws

[MitchellMc]

I think a handyman could do this job, might be worth getting a couple of quotes @Amrad79.

There is just such a stark difference between the rusted and others that appear perfectly new. It makes me think something is wrong with the rusted ones, and the others are fine. It might just be your image, but when I see rusted screws in that condition, the fact the other ones are not speckled with rust and are on their way out, too, is weird.

Roof looks fine to me, but I'd pull out one of the heavily rusted screws to check if the threaded shaft has rusted and check to see if the edge of the hole in the sheet has started to rust.

Mitchell

[Amrad79]

thanks , yes some are rusted and others totally normal, they have a rubber washer underneath would that stop the rust from spreading , do you think l need a roofing specialist to look at it or just a plumber or handyman will be oK, l think l will get a quote from my hire a hubby handyman and other from my local plumber unless you think l should get a roofing specialist to look at it also , so from the look of the photos is it something l should get to more urgently rather then wait, my fear is the rust spreading to the roof

[MitchellMc · Accepted solution]

It would be great to have at least a quote from a roofing specialist, @Amrad79. Provided the roof sheeting hasn't been comprimised, then I think this is a simple case of needing the screws replaced, which doesn't require the expertise or associated cost of a specialist. However, if the roofing specialist quote comes in close to your other alternatives, I've been inclined to go with them as they'll likely get the job done much faster.

Mitchell