White marks on roof

[surf09]

Hi there

Just wondering if someone can tell me what these white marks on a roof means, how to get rid of it, and can I just leave it as it? It's worse on the south facing side.

White marks on roof (north facing):



Non-white marks on the other side of roof (east facing):



Roof it seems is tile or some sort.

Is it salt or tile absorbing water and needs replacing?

Thanks

[Beano]

It could be seagull poo

[jimO]

can yo put up better pictures?

[surf09]

can yo put up better pictures?

Those are the only photos I have.

[jimO]

if its colour steel it could be the colour wearing off, leaving the white undercoat behind, lots of 20 year old colour steel roofs doing this

[artemis]

Best sort it before 25 December or Santa will think he's already been there and fly right past.

[FJW]

Are there any leaks as a result of it? It looks as if its a tile roof so probably just due to the weather....perhaps see if you can spray something like 'spray and walk away' and see if it comes off or combine it with a pressure wash....