emulsion are provided which are useful in imparting water resistance to gypsum products . in one embodiment , the emulsion comprise a plurality of waxes , at least one saponified wax , a complexed starch , a polymerized alkyl phenol , and a small amount of a co - surfactant . in another embodiment , the emulsion comprise a single wax , a balanced dual surfactant system , a complexed starch and a polymerized alkyl phenol . emulsion of this embodiment may be added to hot , even boiling , water without the emulsion separating or curdling . the emulsion of the present invention are stable for extended periods of time when stored at room temperature and do not require the addition of a bactericide . the emulsion of the present invention are pourable liquids at room temperature .