I do this odd shaped looking building and the customer asked me to clean the glass tiles that run in sequense with the roof tiles above the front and back porches,I said I would do it on the next visit and that time is approaching,when I looked closely there is alot of algae build up underneath each glass tile and they seem to be caked in place,was thinking of spraying TFR on and then do the windows as normal and come back to scrub off but the algae is within the overlap so quite difficult to remove,any ideas
