This chapter focuses on the validation of the proposed conceptual framework for adopting modularity methodology in the construction industry. Validation was achieved through expert interviews designed to assess the framework’s relevance, practicality, and applicability within diverse construction contexts. The selection of interviewees was based on their expertise, professional experience, and involvement in modular construction practices, ensuring that insights were drawn from knowledgeable and credible sources. The chapter also outlines the interview framework and approach, which combined structured and semi-structured questions to capture both standardised and in-depth perspectives. This method facilitated the collection of qualitative data that reflects expert opinions on the framework’s strengths, limitations, and areas for refinement. Analysis of the data employed thematic coding, enabling the identification of patterns, emerging themes, and consensus points among experts. To ensure the credibility of findings, measures were adopted to enhance validity and reliability, including triangulation of responses, peer debriefing, and careful documentation of the research process. The validation process not only confirmed the robustness of the framework but also provided critical feedback for its enhancement, particularly regarding stakeholder collaboration, regulatory alignment, and cultural adaptation. The chapter demonstrates that the validated framework offers a sound, adaptable, and practical guide for advancing modularity methodology in the construction industry, strengthening its theoretical and practical contributions.