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How to fix a metal roof leak?

Hi,
I am looking for some advice on fixing this single garage roof leakage.
Since its already sagging and it seems like the damage is beyond repair.

Can someone please guide me if I should just change one panel sheet or engire garage roofing.

Can it be achieved as a DIY?

Scope will be Remove old cladding, capping, and flashings. Install insulation sarking, new battens, and Zincalume cladding with color-matched flashings and cappings. Provide fall protection, clean up the site, and dispose of all rubbish.

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MitchellMc

Welcome to the Bunnings Workshop community @jixie. It's wonderful to have you join us, and many thanks for your question about roofing repairs.

Replacing a single sheet is usually the simplest way to deal with a localised leak, and if you are confident working at height it is something a capable DIYer can manage. The job is mostly a matter of removing any flashings or ridge cappings that overlap the affected sheet, backing out the screws, sliding in the new sheet, and re-fixing everything. The main challenge tends to be matching the profile, so it is worth taking a clear photo of the sheet’s end profile and checking with the Special Orders team to make sure the correct replacement can be sourced.

A full re-roof, which involves sarking, battens, new flashings and a complete replacement of the cladding, is obviously much larger in scope. It is doable as DIY, but only if you are completely comfortable with roof work, fall protection and working methodically through each layer. The bigger question is whether the existing sagging indicates structural issues underneath, because if the rafters have been compromised you will need to address that, not just the sheeting. So a single sheet replacement is generally fine as a DIY fix when the leak is isolated and the structure is sound. A full roof replacement is possible, but it is worth honestly assessing whether the scale and safety considerations push it into professional territory.

Please let me know if you have any questions.

Mitchell

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MitchellMc

jixie

Thanks Mitch.
Do you reckon just getting a cover on top of the leaky part over the roof sheets would help in long run?

MitchellMc

Hi @jixie,

Since the section of roofing is already badly pitted and rusted through, a simple cover over the top usually won’t give you a reliable long-term fix. Once steel has reached the point where it has holes, tapes and sealants struggle to bond properly, and even a mechanical patch tends to be a temporary measure. The only realistic patching method would be to source a sheet in the same profile, cut a small section to overlay the damaged area, adhere it down, and then seal all the edges with a roofing-grade silicone. The problem is that if you are buying a full sheet just to cut a patch out of it, you are getting close to the cost and effort of replacing the entire sheet anyway.

Replacing the full roof sheet is almost always the better option because it eliminates every weak spot in one go and stops you relying on silicone as your first line of defence. A patch will eventually fail because water constantly works its way to the lowest point, and it only takes a small gap for it to get under the overlay and back into the rusted section. If you want something that will last, swapping out that whole sheet is the most dependable and straightforward way to get a permanent fix.

Mitchell

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