the invention relates to improved non - efflorescing cement - free and water - dispersible powder building material compositions comprising a homopolymer or copolymer as binder , useful for the preparation of wet formulations of plasters grouts , waterproofing coatings or mortars for the construction and the civil engineering industry . redispersible dry composition of polymer finish comprising : a powdery organic binder included a polymer obtained by spray - drying or lyophilisation of a dispersion containing said polymer and a protective colloid ; a deprotection agent ; a specific adsorbent filler ; and / or a load ; and / or a water retentive agent ; and / or a mineral rheological agent ; and / or a defoamer ; and / or a biocide ; and / or a pigment . the invention also refers to the methods of preparation of these dry compositions and wet formulations , the application of these latter onto the surface of buildings or civil engineering works , the so obtained coatings as well as the so coated elements . the applications of these wet formulations can be also hardened joints or other hardened products for the construction as well as hardened mass objects . all these hardened products are remarkably water - resistant , non efflorescent and easy to obtain .