Sika 4a Waterstop 5LSika 4a Waterstop is a rapid setting, ready to use waterproofing admixture which can be used to produce a paste for leak stopping against high water pressure infiltration when mixed with water and ordinary Portland cement. Ready to use just add clean water and ordinary Portland cement Does not contain chlorides Solvent free Suitable for use in quick setting mortar for assembly work Rapid setting for quick leak plugging and or fixing