Rust stains on pebbledash- how to get rid for good!

[Crf79]

hi, I have a 1930s house that was extended a couple of years ago. The extension was pebble dashed and then painted white (to match the original part of the house). Since then we’ve been getting a lot of rust stains all over the extension. The builder has been back twice to paint over it, but the stains have always come back. It’s hard to tell if the stains that come back are the original stains or new stains as there are so many! The builder is saying he’ll come back again and this time they will cut out the pebbles that are causing the stains, but basically he says this is normal for pebble dash and I’m getting the impression that this is the last time they’ll treat it...

Does anyone have any advice please?

 

[footprints]

Try Zinsser products maybe allcoat / coverstain or better still give them a ring.
http://www.zinsseruk.com/howto/paint-rust-stained-surfaces/

 

[Crf79]

Thank you, I’ll look into that...

 

[opps]

To be fair to the builder, he has no way of knowing if their are iron particles in the sand/pebbles when dashing.

I have seen people using oil/shellac based paints as a spot primer but it doesn't always work. Puse erhaps they didn't prime a large enough area?

I would defer to Footprint's suggestion to phone Zinsser. Their products aren't cheap but they do make a comprehensive range of "problem solving" paints.

Another alternative would be to use an oil based masonry paint such as Pliolite.