Recurring moisture problems inside the historic huts, Ross Sea region, Antarctica, have been recorded over the past few decades. Particularly serious problems have been experienced at Scott’s Terra Nova hut at Cape Evans, Ross Island, the focus of this study. Logged temperature and relative humidity data were analysed for patterns and for correlation with the external weather conditions. A field trip was carried out where physical parameters of the hut were measured to enable accurate modelling of the indoor air state, along with side projects to determine pollutant infiltration. The model provided individual component mass transfers of the four main mechanisms involved, and allowed ‘What if?’ analysis to be performed. The model was used to determine the effects of current policy on the use of the hut and determine the sensitivity to change. Periods of high relative humidity inside the hut were found to coincide with moisture-laden, northerly weather patterns. Visitor thoroughfare in the hut was not seen to have any lasting effect on the moisture state of the hut, although some local condensation may appear. Ice removal from under the building would remove a source of bulk moisture that has a role in many moisture transactions to the air state of the building. Some small policy changes that would help offset some human-related conditions and improve information gathered in the future have been recommended.