2500asf reroof for existing sfd. If a re-roof project is proposed, the following specifications apply. Existing roofing material shingle proposed roofing material shingle manufacturer gaf brand and model timberline hd color (if cool roof required) sandalwood built-up roofing assembly system number per attached listing report (if applicable) na specific exemption from cool roof requirements (if applicable) na required building inspector field verification (if applicable) na note self-certification by a licensed contractor is acceptable if a signed letter on company letterhead is provided to the building inspector.