Primer G Where to use: Treating gypsum or anhydrite surfaces prior to installing ceramic tiles and stone materials with cementitous adhesives or leveling. Surfaces to be treated must be clean and porous. Dilute with water from 1:1 to 1:3 to protect old floors before levelling, to consolidate residual dusting and provide even absorption of substrate prior to levelling or laying. Apply on perfectly dry gypsum or anhydrite surfaces (reidual moisture content less than 0.5%).... Yes