Stepwise emulsion copolymn. of Et acrylate, Bu acrylate, Me methacrylate and methacrylic acid was found to yield best film-forming seed-core and seed-core-shell type latexes. Styrene gave poorest latexes. Hildebrand's soly. parameters (S), molar refractions (M) and miscibility data of seed, seed-core and seed-core-shell latexes were theoretically calcd. to establish which latex gives the best protective coat for plaster, concrete, and brickwork surfaces. Latex concn., particle size, Huggin's interaction const., surface tension, dissocn. const., equivalent conductance and one at infinite dilution were detd. in relation to intrinsic viscosity of the latexes. The S and M of the copolymers prepd. were found to indicate the dispersive. systems that yield most durable latexes and coats that have best phys., mech., and chem. properties. A correlation appears to exist between the theoretical and exptl. data.