Zinsser Gardz is a water-based, high-performance sealer for all porous surfaces such as new gypsum drywall, joint compound and spackling. These porous surfaces can make final coatings appear uneven and patchy. Gardz penetrates deep into the surface and uniformly seals, creating a moisture-resistant film that protects drywall from blistering, tearing and other damage when redecorating in the future.
It has good alkali-resistant properties, which means it can be applied to high pH surfaces. Gardz is suitable for sealing damaged drywall, new drywall, spackling and joint compound, skim coats, plaster, calcimine, uncoated wallpaper, wallcoverings adhesive residue and textured paint finishes.

Before application of Zinsser Gardz, the surface must be clean, dry, sound and free of contaminatio