Rock art monuments provide a link to our ancient cultural pasts, they possess seeming permanence but are sensitive to their environment. The increasing emphasis on non-destructive testing and demand for thorough characterisation of cultural heritage material in situ requires the development of advanced diagnostic methods, providing the motivation for this work on the application of optical coherence tomography, hyperspectral imaging and nuclear magnetic resonance to rock art panels. Optical coherence tomography is shown to be an effective method to determine the grain size distribution and hydraulic conductivity of historic sandstone in situ. Studies were performed on historic sandstone headstones to demonstrate the relationship between the hydraulic conductivity of sandstone and the type and severity of weathering features present. A study of rock art panels in situ is given, to characterise the host rock and provide quantitative assessment of the vulnerability of the panels to weathering processes. The relative impact of natural weathering and anthropogenic damage is shown and a comparison between the characteristic of a proxy sample and the rock art panel itself is provided to highlight the importance of non-destructive in-situ methods for the monitoring and assessing of the vulnerability of rock art monuments. Hyperspectral imaging is demonstrated as an effective technique to determine the presence of moisture in stone, while nuclear magnetic resonance measurements show limitations for use in situ in open air locations.