40sf rerrof for existing sfd. If a re-roof project is proposed, the following specifications apply. Existing roofing material shingles proposed roofing material shingles manufacturer owens corning brand and model tru def color (if cool roof required) na built-up roofing assembly system number per attached listing report (if applicable) na specific exemption from cool roof requirements (if applicable) r38 in existing roof required building inspector field verification (if applicable) r38 in existing roof note self-certification by a licensed contractor is acceptable if a signed letter on company letterhead is provided to the building inspector.