How to fix rust on corner of rendered wall?

[jackbrown]

Hi, I've got rust forming on the edges of the exterior rendered wall every 2-3 months, I've read other posts and there's a similar one near the beach but my house is in the city area, so no salt in the air.

It only happens to the corner edge of the wall and throughout the years I've been using the same paint to paint over and over it but the rust continues to form.

It's not appearing to the whole edge, only sections of it.

Any idea of a more permanent fix, thanks heaps.

[EricL]

Hello @jackbrown 

Thanks for sharing your question about your rusting corner on your rendered wall. I suspect that water has somehow entered the rendered wall and is exiting through the steel corner trim. Unless the source of the leak is found and addressed, it will continue to get rusty despite sealing it in paint. I propose engaging the services of a leak detection service and they can try to track down where the water is coming from. Once the source of the leak has been identified you can either use silicone or a chemical sealer to patch the leak. The corner can then be properly sanded down and renderd if necessary before painting it over.

Let me call on our experienced members @Dave-1 and @AlanM52 for their recommendations. 

If you have any other questions we can help with, please let us know.

Eric

[AlanM52]

Hi @jackbrown,

The rust looks like it starts at your recessed balcony and I'm wondering if the water is finding it's way across from the neighbors 'flush' balcony.

Maybe redirected at that ledge and the rendering looks a bit rough?

Cheers

[Dave-1]

Good Morning @jackbrown 

It looks like the water has managed to get into/behind your mortar, and thats why the rust keeps on returning. You need to sort out where the water entry point is (see @AlanM52's pic) and fix the issue first otherwise it will constantly come back until failure of the steel edge from rusting @EricL has mentioned for the corner.

Painting and sanding is a cosmetic fix, it will work for a bit but the underlying issue will keep on coming back. I do not know about the chemical fixing that @EricL but it does sound interesting. 

Dave

[jackbrown]

Thanks everyone for helping out.

There’s actually metal capping at the top and they are in good condition, unsure where the water is getting into it, refer to images below.

Similar rusting also happening to our duplex neighbour too.

   

 

[jackbrown]

Thanks Alan, if you refer to the other photos, the wall isn't flush to the balcony.
The rough render or the "bubbling" seem to appear from the constant rain couple weeks ago.

[EricL]

Hello @jackbrown 

Let me tag @AlanM52 to make them aware of your comment. If the water is not coming from the balcony, it could possibly be coming from a higher point along the structure. The appearance of rust at that very specific spot leads me believe that there is a leak occurring or a certain portion of flashing has failed at the top of the structure.

Eric