You can also use GGC Oman Gypsum forwall plastering and as an adhesive for gypsumboards and other gypsum based items on concrete and cement walls. ... Colors: White / snow white: Initial setting time > 6 min. Final setting time >18 min: Water stucco ratio: 70-75%: Compressive Strenght: 9 N/mm2 after seven days: Flexural Strenght: 3 …