Sustainable financing models for long-term viability in social and affordable housing projects in South Africa

The lack of sustainable financing options remains a critical constraint on the development of social and affordable housing, particularly in rapidly urbanising contexts such as South Africa. High and volatile borrowing costs, short debt tenors and rising construction and operating costs undermine the long-term viability of projects that must remain affordable to low- and moderate-income households. This study investigates sustainable financing models that can support the long-term financial viability of social and affordable housing projects, with a focus on public–private partnerships and blended-finance mechanisms that balance affordability, fiscal prudence and portfolio resilience. A structured desktop research design, guided by the PRISMA 2020 framework, was employed to identify, screen and include relevant evidence from peer-reviewed literature and grey sources (policy reports, programme evaluations, technical notes). Desk-based profiles of selected South African social housing projects established a local baseline, and comparative insights were drawn from international cases in Europe, North and Latin America, and Asia. Data were synthesised using a project-finance lens, focusing on weighted average cost of capital, debt-service coverage ratios, leverage, subsidy per unit and portfolio durability. The review finds that blended models combining government subsidies, concessional loans, equity contributions and credit-enhancement tools within clear governance frameworks can materially reduce the effective cost of capital, stabilise cash flows and crowd-in institutional capital, especially when supported by pooled vehicles and labelled social or green bonds. The study distils these findings into a South Africa–specific options menu and financial-modelling framework, and recommends policy and regulatory adjustments on guarantees, concessional lines, municipal land and data standards, with potential applicability to other emerging markets.