This paper reports the preparation and characterisation of nano-structured composite coatings consisting of montmorillonite-type silicates embedded within polymer matrices. Water-borne acrylic and polyurethane resins were employed as matrix, and hydrophilic or organically modified nano-particles of montmorillonite (MMT) as reinforcement. Emphasis is posed upon the preparation of the coating and an overview of the major steps involved is presented. The choice of a suitable solvent for the preparation stage is based on the values of the solubility parameters. The characterisation techniques that are used include X-ray diffraction analysis, gas permeation measurements and IR spectroscopy. The results highlight the significance of the selection of appropriate ingredients and the knowledge of the interactions between the clay particles, the organic matrix and the solvents used for the preparation of the coating.