The growing use of artificial intelligence (AI) and data-driven methods in architectural heritage research requires structured and reusable semantic units to support consistent modelling, annotation, and knowledge alignment. In this context, Historic Building Information Modelling (HBIM) can serve as a semantic anchor by linking surveyed geometry with object-based representations and non-geometric information. However, current HBIM workflows remain semantically fragmented: point cloud segmentation often relies on project-specific labels, object modelling adopts inconsistent decomposition and naming logics, and semantic enrichment is frequently implemented through custom parameters without a shared component-level framework. Although Industry Foundation Classes (IFC) provide the most widely adopted canonical structure for interoperability, their standard entities are often too coarse to represent heritage-specific subcomponents. To address this gap, this study proposes an IFC-compatible semantic framework for component-level representation in HBIM. The framework combines a canonical IFC-aligned layer with a heritage extension layer and introduces a mapping strategy for representing semantically meaningful subcomponents without modifying the core IFC schema. A Serliana arch on the church of SS. Paolo e Barnaba in Milan is used as a case study to illustrate the implementation of the proposed approach. The study establishes a preliminary semantic foundation for component-level heritage representation in HBIM, providing both a conceptual basis for structuring heritage subcomponents and an operational basis for their IFC-compatible implementation. This foundation may also support future developments in ontology alignment and cross-modal AI applications, where stable semantic anchors are required for data integration and annotation.