Zinsser Mold Killing Primer is a water-based fungicidal protective coating that can be used to paint over and kill all existing mold, mildew, moss, fungi, odor causing bacteria and any other fungal organisms. The Mold Killing Primer contains an EPA registered antimicrobial to prevent the growth of mold, mildew and other fungal organisms on the paint film. The Mold Killing Primer also aides in covering residual microbiological and fungal stains. Paint directly over mold. Binds chalky siding, masonry and metal Great for use under wallcovering Interior/Exterior Water-Based Zinsser/Rustoleum Corporation