The South African Oxygen Permeability Index test (OPI) and Swiss Torrent air permeability test (TPT) are well-established methods used for gas permeability evaluations of concrete infrastructure. Comprehensive laboratory experiments have shown the compatibility of the two methods as a combined approach for enhancing the durability assessment of the concrete cover layer. However, this synergy has yet to be investigated under ambient conditions. This paper explores the practicality of an integrated method using the OPI and TPT methods together. Concrete panels were manufactured and exposed to ambient conditions in Cape Town, South Africa. Gas permeability tests were carried out at 28 and 56 days to observe the responsiveness of the OPI and TPT to variables such as water/binder ratio (w/b), binder type, and age. The results indicate that the two methods correlate reasonably well with existing data in dry site conditions. However, further investigations are warranted to understand the influence of moisture on the correlation between the TPT and OPI in moist conditions. This work suggests an approach to implement a combined methodology for gas permeability assessment. The approach provides insights into the benefits of combining non-destructive and destructive methods to enhance the durability evaluation of concrete.