Evaluating the Economic Impact of Alternative vs. Conventional Construction Materials for Residential Projects in Tanzania: Integrating Environmental and Social Criteria

Previous research in Tanzania has focused on comparing the mechanical and environmental properties of sustainable building materials (SBMs) with those of their conventional counterparts; however, there remain limited contributions in assessing the economic impacts associated with this trend. This significantly hinders the adoption of SBMs in residential construction, as economic viability remains a critical factor in material selection in developing countries, such as Tanzania. Using cost-benefit analysis (CBA), this study addresses this gap by evaluating the economic viability of SBMs in comparison to conventional materials for residential building projects in Tanzania, while considering environmental and social factors. To achieve this aim, a comparative analysis of two material alternatives, namely compressed stabilised earth blocks (CSEBs) and conventional concrete blocks, was conducted based on predefined criteria, including cost, local availability, and ease of use. Findings reveal that CSEB walls are approximately 18% more cost-effective than concrete blocks, offering enhanced constructability and reducing environmental impact, rendering them a highly recommended option for sustainable residential construction. The novelty of this study lies in the application of CBA, which is predicated on developing unit rates per unit scale through a cost breakdown, enabling stakeholders to adjust cost components at a granular level for informed decision-making. Practically, this study provides a cost-based decision-making framework for selecting SBMs in Tanzania while promoting awareness through suggesting an improved format of price list that integrates sustainable alternatives. However, the study is limited by its focus on a specific region and materials, as well as the qualitative treatment of environmental and social criteria. Future research should expand the analysis to include broader aspects, thereby better elucidating the overall suitability of SBMs in diverse contexts.