This paper deals with the evaluation of different consolidation treatments of the excavated foundation of the Poseidon Temple in Poros island, Greece, made by a friable, low strength type of local limestone. Four types of commercial products have been studied in the laboratory, grouped in three categories: inorganic consolidants, acrylic emulsions and silane-based materials. The evaluation was based on the performance characteristics of the treated specimens, incorporating parameters of pore structure, water absorption, water repellence, mechanical strength and durability behaviour, along with compatibility, aesthetic issues and the impact of the main deterioration agents that are responsible for the degradation of the above monument.