Here the use of the IGAN system for in-situ TGA and neutron diffraction is proposed in order to study the de-hydration of four proton conducting materials. The selected materials are all highly oxygen deficient perovskite systems that show large relative mass changes on de-hydration, e.g. ~ 2-3 %, and display a range of hydration behaviours, from structural transitions (BaTi0.3In0.7O3-d) to the unexpected absence of a significant chemical expansion (BaTi0.5Sc0.5O3-d and BaTi0.3Sc0.7O3-d). Critically, the simultaneous approach should allow us to monitor the changing crystal structure as a function of proton concentration based on the TGA data. In addition we plan to monitor the de-hydration reaction through refinement of the oxygen site(s) occupancies and correlate this with the recorded mass changes. Through this a better understanding of the hydration reaction will be gained.