How to fix leaking metal roof?

[perthian]

Good day helpful experts, I have a metal roof that's leaking.

I've been given options to 1) replace the whole roof or 2) to remove the screws and replace with metal patches and refasten with new screws to the ribs.

I'd like to pick the repair option as it's 1/6 the cost of roof replacement. Does it look like the repair will hold, if it's done properly by a roof tradesman? And what's the most durable type of screw Bunnings can recommend?

I've been told the roof screws have been installed wrongly on the pans/valleys rather than the ribs/ridges. And some of the rubber rings around the screws appear to be cracked. And one of the screws is even missing.

It's not common to put screws on the pans in Australia but in the US, that's recommended if the right screws are used so the sheets have less flex with strong winds (https://www.metalroofingsource.com/install-metal-roofing-fasteners/).

Thanks very much for any advice you'll be able to provide.

screw with cracked rubberscrews in pans instead of ribsscrews in pans instead of ribsroof has existing patchesmissing screw

[JacobZ · Accepted solution]

Hi @perthian,

Thank you for your question about a roof repair at your property.

The position of the screws is relative to the location of the installation and the profile of the sheeting used. This profile of the roof sheet is referred to as Trimdeck, and in a roofing application, the screws should go through the ridge, not the valley. You can see this in our supplier Lysaght's Trimdek Brochure.

With this being said, a roofer may be able to give you a solid repair that will last a good amount of time, but ultimately, they are working with materials that weren't installed correctly to begin with, so the repair will only be as good as the initial installation was.

Personally, I would be looking to replace the roofing materials, but I am not the one who has to bear the cost of the repair.

My advice would be to weigh up whether you think you will get 1/6th of the expected life of new sheets out of the repair. If so, then it is probably worth repairing. If not, then replacement is the best option.

Allow me to tag @JoeAzza, @Noyade, @Nailbag and @Dave-1 for their opinions.

Jacob

[perthian]

Thanks so much Jacob! 

That's super helpful, including the brochure reference - much appreciated! 🙏

[Dave-1]

Evening @perthian 

That is a pain, Short term I would go for a repair with silastic and flat squares of metal to cover the old screw holes. (Silastic in the hole and around it, then plate pushed down so the silastic forms a solid bond on all four edges) You could do that yourself without a lot of trouble (Just make sure you only walk in line with the roof trusses as shown by the long run of screws. As you dont want to buckle the roofing)

At the same time as the plates going down I would be putting new screws into the ridges to secure the sheeting. Something you could also do if you are not concerned about heights. With teh screws dont overtighten them, they just need to be snug and the rubber compressed a little between the screw head and the sheet of iron.

Dave

[perthian]

Thanks very much @Dave-1..

Would you please let me know what Bunnings products to look at for the silastic and screws?

I saw the dome screws being used in the existing roof but it appears they're mainly for polycarbonate sheets.

[Dave-1]

Morning @perthian 

I just had a search on the Bunnings site and came up with these as an example 

Zenith 12G x 50mm Galvanised Dome Washer Head Roof Screws - 50 Pack There will be larger boxes for sure that work out cheaper.

Depends on the height of the ridge of you sheet or metal is all. I would like at least 25mm into the timber type deal if it was my roof.

Sika 300ml Translucent SikaSeal Roof And Gutter Silicone Sealant  for the silastic. 

Dave

[perthian]

Great! Is the Zenith dome screw ok for the metal sheet? The item description says "fixing polycarbonate sheets into timber"..

[Dave-1]

Morning @perthian 

I do not know, I would be presuming so, I generally read the back of the packet to see if they are suitable (yeah I spend a lot of time making sure its right) I would wait until one of the Bunnings team members confirms or not. You need to seal your attachment point through the screw so dome rubber is what I would be looking for.

Dave