27 sqft reroof for existing sfd. If a re-roof project is proposed, the following specifications apply. Existing roofing material: wood shake proposed roofing material: comp manufacturer: gaf brand and model: grand canyon color (if cool roof required): built-up roofing assembly system number per attached listing report (if applicable): specific exemption from cool roof requirements (if applicable): installing radiant barrier required building inspector field verification (if applicable): yes in attic note: self-certification by a licensed contractor is acceptable if a signed letter on company letterhead is provided to the building inspector.