Hi Guys,

I have been browsing this site for the last month and learning a lot. Thanks a lot.

I live in Ireland where we use cement tile and cement fibre slate or natural slate. I have been experiminting with roof cleaning for the last 18 months but need to finally get it right. Up to now I have stayed away from using SH but couldn't find a way to remove the black algae from the slate.

Is there any easily available chemical that I can use to mask the smell of SH. It is cost prohibitive to import any form of chemicals from the US. I have attached two pictures of a red fibre cement slate roof that I need to clean. Your ideas would be greatly appreciated.

Thanks again

Michael 

GM Services