The pore structure of porous building materials, which often covers a wide range (from nanometers to millimeters), plays a crucial role in the material functional properties. This study provides a comprehensive pore structure characterization of ceramic brick, a widely used building facade material, through multiscale and multimodal imaging techniques. To address the inherent conflict between imaging resolution and field of view, an “image chain” of seven three-dimensional greyscale image sets is acquired via X-ray Computed Tomography and X-ray Microscopy, with voxel sizes progressively increasing from nanometers to micrometers. Furthermore, a novel bootstrapping-based method is introduced to integrate statistical data from the image chain, enabling a complete pore structure characterization across the full range of scales. Following the image acquisition and processing, the single-scale pore networks are extracted using the maximal ball method. Key statistical information from these partial pore structure representations is systematically analyzed, distinguished, and then integrated. The proposed integration approach identifies the most reliable single-scale pore networks across the full pore size spectrum, achieving a total porosity of 32.5%, which closely matches the experimentally measured value of 32.6%. Considering the computational cost, preliminary validation on a relatively small full-scale pore network demonstrates reasonable predictions on hygric properties, while larger pore networks are currently being developed and simulated for further validation.