The paper aims at introducing a discrete (network) approach to modelling transport of condensable vapours in mesoporous structures. Such models possess the potential for improving the understanding of the mechanisms responsible for the observed transport behaviour. The basic elements of a typical pore network representing a mesoporous medium are summarized and the current state concerning the simulation of the related phenomena is given. The main processes involved (adsorption, mass diffusion, surface flow, capillary condensation) are simulated over the entire range of relative pressure. Finally, the effects of material structural parameters (average pore radius, pore size distribution and standard deviation, pore connectivity) and other relevant factors (relative pressure. temperature, resistance to surface flow, total pressure drop) on vapour permeability are presented and the future research directions are pointed out.