Rust roof screws

jimbo73 · Mar 17, 2024 10:27 am

Hi l have a color bond roof 12 years old and l live 4 km from the coast, l noticed about 20% of the roof screws have some rust on them and the other 80% look OK with no noticeable rust, could l just replace the screws with rust and keep the rest with that have no rust or do all need to be replaced, someone l spoke to at Bunnings said its strange some of the screws are rusted but other have no rust at all, he said some of the screws could have been defective and not rust treated. Who would be the best person to get to replace the screws a roofing company a plumber or a handyman, and roughly what do you think the cost would be to replace all the screws on an average sized house

BuildingandLegal · Mar 17, 2024 10:08 pm

The rush is caused by roofers using impact drivers without a torque setting which damages the head's coating on the screw, when being installed,
The trouble is that when you replace the screws you will take the old screws out of a hole and insert the new screws in the same hole, this means that the screws wont have the same strong grip as the old screws. Roof replacements require new battens for this reason.

Can i suggest take 6-10 screws out from random locations over the roof and confirm if the rust is just surface around the hex-head, and if there is any rust on the shaft below the rubber washer. If they all show no rust below the washer then your roof is still weather tight, if the rust is only surface rust on the hex-head, wire brush them (IN PLACE) spray some cold gal on the heads then spray them with the same colorbond colour as your roof.

jimbo73 · Mar 18, 2024 3:29 pm

l spoke to my plumber he said theres two options they can paint the screws with cold gal paint which is only a few hundred dollars but will only last a few years or they can replace all the screws for $2,000, which is a better option, l was thinking as only about 20% of the screws have rust on them and the other 80% look normal it might be better just to have them painted and check them in a year. My main concern is that rust does not spread from screws to the roof, if the screws are painted will that contain the rust for a couple of years and l can decide them if l want to get them all replaced

Pulse · Mar 18, 2024 8:32 pm

The rust won’t spread to the roof sheets, spraying them will look patchy as the colorbond will already be faded. The rust is only cosmetic (to a point)

I’d wait until enough have rusted to make replacement worthwhile and use either C4 or C5 screws.

https://www.no1roofing.com.au/climaseal ... ng-screws/

If the battens are deteriorated then go up to 65mm screws, 50mm are the norm for corro , 65 for trimdek gives similar wood penetration.

jimbo73 · Mar 18, 2024 8:48 pm

Pulse

The rust won’t spread to the roof sheets, spraying them will look patchy as the colorbond will already be faded. The rust is only cosmetic (to a point)

I’d wait until enough have rusted to make replacement worthwhile and use either C4 or C5 screws.

https://www.no1roofing.com.au/climaseal ... ng-screws/

If the battens are deteriorated then go up to 65mm screws, 50mm are the norm for corro , 65 for trimdek gives similar wood penetration.

thanks ,l have a photo below, only about 20% of the screws have any signs of rust the other 80% have no rust, l think my plan
is to have the rusted screws painted with cold gal paint which will cost almost nothing and in a year l get a full replacement of all the screws on the roof, Do you think the cold gal paint should stop the rust for a year and it would be safe to wait a year
to have them all replaced. Also someone mentioned becasue the new screws will be placed in the same hole as the old ones they might not have a tight grip , if that happens and the roof becomes lose does the company that installed the screws have to fix the problem at their own cost or would l have to pay
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Pulse · Mar 19, 2024 6:15 am

yep I think not urgent, screws not likely to come loose, hand tighten a few and you’ll get an idea of how good condition the batten is, I think the battens should be good still at 14 years. You could hsppilh leave it another 3-4 years, the cold gal is really not achieving much.

jimbo73 · Mar 19, 2024 1:01 pm

Pulse

yep I think not urgent, screws not likely to come loose, hand tighten a few and you’ll get an idea of how good condition the batten is, I think the battens should be good still at 14 years. You could hsppilh leave it another 3-4 years, the cold gal is really not achieving much.

l spoke to my plumber we decided to replace the rusted screws and keep all the screws with no rust, it will only cost a few hundred

jimbo73 · Mar 19, 2024 1:01 pm

Pulse

yep I think not urgent, screws not likely to come loose, hand tighten a few and you’ll get an idea of how good condition the batten is, I think the battens should be good still at 14 years. You could hsppilh leave it another 3-4 years, the cold gal is really not achieving much.

l spoke to my plumber we decided to replace the rusted screws and keep all the screws with no rust, it will only cost a few hundred