Rust Spots on Timber Windows & Doors (?)

[SeaGull1]

Hi,

I work for a small developer and looking for an opinion on what's happening here. Small rust marks appearing on window frames and doors and it's a bit of a mystery as to what's causing it. Any ideas?

Thanks
[GALLERY=media, 106088]Door stain by SeaGull1 posted 17 Feb 2021 at 8:09 AM[/GALLERY][GALLERY=media, 106087]Window Stain1 by SeaGull1 posted 17 Feb 2021 at 8:09 AM[/GALLERY][GALLERY=media, 106086]Window Stain2 by SeaGull1 posted 17 Feb 2021 at 8:09 AM[/GALLERY]

 

[MMarve]

Looks to me like iron fallout that is then rusting. Are you near to a railway line or industrial site where there might be excess iron fillings in the air?

You can see it a lot on cars, there is specific iron fallout remover products that you use to disolve the iron before polishing your car etc.

 

[SeaGull1]

No railway line or industrial site but it's a building site. Grinder disc residue from cutting slabs etc?

 

[MMarve]

100% yes. Should settle down once the building works have finished. In the meantime, you should be able to use some ironout type product for cars (Halfords if you want a quick and easy win). Spray it on, leave it to start working for 5 minutes (it normally turns purple or something and streaks down as it dissolves and then hose off.