USG Sheetrock Brand Durabond 20 Joint Compound is a setting-type compound that provides faster finishing of drywall interiors, even under slow drying conditions. Rapid chemical hardening and low shrinkage permit same-day finishing and usually next-day decoration. It features exceptional bond, virtually unaffected by humidity extremes, and is are ideal for laminating double-layer systems, particularly fire-rated assemblies, and for adhering gypsum panels to above-grade concrete surfaces. May also be used for surface texturing and for filling, smoothing and finishing interior above-grade concrete. Note: Setting-type joint compounds should not be used for skim coating due to dryout concerns.