How to treat rust on inside of gutters?

Our gutters have a fair degree of rust inside them, looking to extend the life of the gutters before corrosion completely takes over and starts giving us holes. A roofing contractor that’s recently done some work on the roof recommended bitumen paint, but would it also be worth treating the gutters with rust converter before I apply the bitumen paint? I’m just a bit concerned the bitumen paint won’t adhere to the rust if I don’t treat it with anything beforehand. Looking for the best option that doesn’t involve sanding/scrubbing the rust off.

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Comments

Akanksha

Hello @Brendan9632,

A warm welcome to the Bunnings Workshop community. We're excited to have you join us and look forward to seeing and assisting you with your home improvement and garden projects.

Many thanks for your question. I'm sure our resident D.I.Y. expert @EricL will be happy to assist once he's back online on the site later today. In the meantime, let me tag some of our helpful Workshop members @kermac, @Dave-1 and @Noyade for their thoughts.

You might also find this previous discussion helpful: How to repair rusted gutters?

Akanksha

Dave-1

Good Morning @Brendan9632

Rusting gutters 😕 ahhhh I didnt do anything to mine until I could see stars through them.... (lot of holes lol) Then I had to replace them.

Whatever you use I would make some effort to remove the existing rust/rust flakes 😕 I would suggest a wire brush and scrub away. There are rust preventers you can use on the metal afterwards and then bitument paint would work but that is sticky stuff! Ive used it once before on a wall and it was a painful job in the open let alone within a gutter. Think molases and sticky plastic.... (you are right in saying the bitumen paint wont adhear to the rust)

The paint shop in bunnings may have some other paint that isnt so "clingy" 🙂

Dave

EricL

Hello @Brendan9632

Thanks for sharing your question about treating the rust on your gutters. It's great that you've received excellent advice from @Dave-1. I'm in total agreement with using a wire brush to clear the gutter surface of rust. Unfortunately, it's not recommended to use rust converter on galvanized surfaces.

It's a bit of a tricky situation as cleaning the galvanized surface too much might damage the gutter itself. In regards to the bitumen paint, I suggest having a look at Crommelin 1L Exterior Grade Brushable Waterproofer. Should you run into holes in your gutter, I recommend using Consolidated Alloys 50mm x 3m Weatherproof Byute Flash Flashing Tape. Make sure to use it on the clean side of the gutter and not on the rusted surface.

Let me call on our experienced members @TedBear and @JoeAzza for their recommendations.

If you need further assistance, please let us know.

Eric

JoeAzza

@Brendan9632 That’s good advice from @Dave-1 and @EricL , this is exactly what I did with my colourbond guttering, instead of using a wire hand brush, I used a wire wheel on an angle grinder, it removed the rust, however , it was a bit aggressive creating small pinholes, I ended up using the same products recommended by @EricL

so far it’s been approximately 3 to 4 months since it was done, so far no more leaks. I also installed another downpipe , the guttering was leaning away from the original downpipe, for me a quick fix was to add another downpipe

Noyade

Morning @Brendan9632

"Looking for the best option that doesn’t involve sanding/scrubbing the rust off."

I look forward to seeing options that don't involve hard work - would have been useful to me twenty years ago. For me, it was a length of guttering that I wanted to preserve as it is the original heavily galvanised guttering from the late 1940s. Hindsight says I should have got it replaced.

After a lotta hard steel-brushing - I used a bitumen putty and then a brush-on. I did this in summer when the metal was hot and the bitumen less viscous. But in the end, it's a band-aid solution.

It worked - but physically I doubt I could do it again.

Best of luck to you. 👍

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