Offsite and Modular Construction for Saudi Giga-Projects and Housing Delivery: A Review of Drivers, Barriers and Enablers, and a Design-Led Readiness Maturity Model

Saudi Arabia is trying to deliver housing and giga-project accommodation at a pace that conventional wet construction struggles to sustain. The Ministry of Municipalities and Housing has set a target of 40% of new houses built with modern methods of construction (MMC) by 2030, and its Modern Building Initiative supports six MMC technologies and has financed more than 22 factories. Yet the peer-reviewed evidence on how offsite, modular and prefabricated construction performs in Saudi conditions is thin and scattered. This review brings together Saudi and Gulf empirical studies (surveys, case studies, economic modelling and risk analyses) with the main international reviews on modular integrated construction (MiC), prefabrication and design for manufacture and assembly (DfMA). A scoping search in OpenAlex on 6 November 2026 returned 38 records for Saudi-specific offsite terms, of which only eight dealt with building offsite construction on title screening; targeted searches and citation tracking raised the final base to 37 peer-reviewed sources, supported by 13 official and industry sources for policy facts. The evidence shows that speed, labour dependence and quality drive interest, while cost, late design freeze, supply-chain gaps, transport limits, regulatory routes, skills and a strong preference for traditional methods hold adoption back. The Saudi studies repeat the international pattern, but with two local features: very high reliance on expatriate site labour and a policy push that is ahead of design practice. The paper proposes the Saudi Offsite Readiness Model (SORM), with seven dimensions, five maturity levels, 28 measurable indicators, a weakest-link scoring rule and a stage-by-stage checklist written for architects. A research agenda closes the paper.