Moisture ingress in building fabric from wind-driven rain (WDR) is an important component of poor building envelope performance. To relate the WDR load to known issues from moisture in traditional buildings, it is important to identify localised WDR loads at different parts of a structure. Additionally, to understand the total surface wetting it is essential to consider the interactions between WDR droplets and the façade, including surface water runoff. Several methods can be used to calculate WDR loads on building facades, such as computational fluid dynamics (CFD). Established tools for assessing WDR loads with CFD (such as OpenFOAM and windDrivenRainFoam) are used to analyse loads only to the interface, typically ignoring the effects of ad- and ab-sorption, as well as the resultant surface run-off. As well, they are typically computed with relatively low-resolution 3D models, which do not incorporate important drainage and drip-detailing of heritage buildings, such as string courses. This presentation will introduce preliminary results of using smooth particle hydrodynamics (SPH) to explore the opportunities afforded by this CFD approach in combination with high-resolution 3D digital documentation data, particularly the ways in which it can be used to characterise imbibement and surface run-off. SPH is a Lagrangian method for simulating fluid flow; it is known for its ability to handle complex fluid phenomena, such as free surface flows, fluid-structure interactions, and simulations involving large deformations. In this paper, case studies will illustrate multi-scale CFD simulations for traditional buildings. SPH simulations of surface water runoff using high-resolution 3D geometric model data are used to identify and relate water pathways to building defects associated with porous masonry decay.