The durability of reinforced concrete (RC) structures is dependent on the resistance of the concrete cover to ingress of aggressive substan- ces from the environment that initiate and sustain the corrosion process. The concrete cover’s resistance is dependent on its thickness and penetrability. In South Africa, the performance-based approach developed and implemented is through the use of Durability Index (DI) tests that provide a measure of penetrability. In addition, cover depth measurements are made to verify for compliance with limit values. The main focus of the paper is a comparison of the oxygen permeability index (OPI) and cover depth values from in-situ and precast structural ele- ments to evaluate the degree of control exercised in construction. It is observed that both the average values for OPI and cover depth of pre- cast and in-situ structural elements complied with the limit value provided in the specifications. However, precast elements had a lower variability in measured values indicating that a higher level of control is exercised.