What is the estimated coverage rate on slate as an anti-graffitiant? enegren February 23, 2024 FAQsFirst 125-175 Square Feet Per Gallon. Second coat 135-185 Square Feet Per Gallon.Post navigationPrevious Previous post: What is the estimated coverage rate on stucco as an anti-graffitiant?Next Next post: What is the estimated coverage rate on sandstone as an anti-graffitiant?