Results of a study aimed at observing the process occurring in porous and soft limestones, such as bihacite, when exposed to rainwater. Bihacite prisms were exposed to repeated long-term wetting and drying cycles using water with a natural CO₂ content. Rebound steel ball, ultrasound measurements and petrographic examinations were carried out to determine the physical properties of the prisms before and after 50 cycles. A gradual decrease in propagation velocities of longitudinal and transverse waves and an increase in the rebound of the steel ball measurements supported the petrographic observations of a change both in the porosity of the interior and the exterior surface density. An excellent description of bihacite is provided.