Detecting organic additives in ancient mortars is significant to be carried out as far as mineralogical, chemical, and physical investigations. That characterisation allows understanding the technology of those mortars and is important to make appropriate decisions in conservation works. Previous characterisations of organic additives in mortars, including jointing and flooring ones used in the Red Monastery located next to Anba Shenoute monastery, have shown the presence of proteins in flooring mortars specifically. This study aims to confirm the addition of protein-based materials in flooring mortars in Anba Shenoute Monastery which almost dated back to the same period (4th-6th century AD). Samples were taken from different flooring mortars and underwent wet chemical analysis, using Comassie Brilliant blue test. Results confirm the addition of proteinaceous additives, raising the probability of intended use for enhancing properties of flooring mortars.