Stain-blocking polymers, as well as primers, kits, and methods that include such polymers, wherein the stain-blocking polymer is an emulsion latex polymer including interpolymerized monomers including: at least 1 wt-%, based on the total weight of the interpolymerized monomers, of one or more acrylic acid ester monomers of Formula (I):

RO—C(O)—CH═CH2

wherein: R is a branched alkyl group having a tertiary carbon atom, a cycloaliphatic group, or a combination thereof; optionally, one or more (meth)acrylate monomers selected from n-butyl (meth)acrylate, ethylhexyl (meth)acrylate, methyl (meth)acrylate, and combinations thereof; optionally, one or more wet adhesion monomers; and optionally, styrene; and wherein the stain-blocking primer includes at least 10 wt-%, based on the total nonvolatile weight of the primer, of the emulsion latex polymer; an aqueous carrier; and optionally, one or more additives selected from a surfactant, thickener, coalescent, biocide, mildewcide, colorant, and combinations thereof.