CE MARKED & KITE MARKED BS EN 12150. Roof rooflight lantern skylight window triple glazed self clean glass 14sizes routine maintenance of self cleaning glass normal weather with daylight and occasional rain will keep the coating activated and self-cleaning. We recommend when installing your rooflight it is fitted with a slight fall to aid water to run off the glass (For units 1000mm x1000mm and smaller set the roof light at an angle of 40mm for every 1000mm Run For rooflights over 1000mm set the roof light at an angle of 40mm for every 1000mm Run).