MasterSeal 588 An elastomeric cement based waterproof coating for concrete and masonry How does MasterSeal 588 work? MasterSeal 588 powder is a blend of Portland cements, selected silica sands and modifying agents. When mixed to a slurry consistency with MasterSeal 588 liquid, an acrylic polymer emulsion, it can be easily applied by brush or roller. It cures to give an elastomeric flexible membrane that remains flexible even when submerged.