This study aims to formulate a ceramic compound for coating walls to be used as protecting barriers at image diagnostic centres, with the purpose of reducing the radiation doses to which professionals and the public are exposed. The attenuation properties towards ionising radiation of different commercial ceramic materials and formulations were experimentally studied using X-rays with effective energies between 20 and 55 keV and theoretically using Archer's model for the calculation of protective barriers. Those samples that presented larger densities and attenuation coefficients were selected, considering the production process facility and low cost. The samples based on the ceramic support grês were chosen, owing to their attenuation properties and wide application as a coating material. Different grês formulations were simulated and evaluated applying the software XCom and TBC model for X-ray spectra generation and the results were compared with reference material containing 4 mm of lead.