Abstract: The invention relates to a method of waterproofing the surface of a polymer work piece. The aim of the invention is to prevent liquid or gaseous, hydroxyl-group (OH group) containing substances, such as water, vapor or glycerol, from diffusing into a polymer surface. To this end, the work piece is treated with at least one organic solvent that blisters the surface of the polymer work piece, thereby diffusing at least one waterproofing agent dissolved in the solvent into the surface of the polymer work piece, said waterproofing agent being a silicon-organic compound. The solvent is allowed to react and is then removed from the polymer work piece, whereby at least a part of the waterproofing agent remains bound in the surface of the polymer work piece.