Understanding sustainability – the case of building blocks in Tanzania and Uganda

Abstract

Purpose The purpose of this paper is to describe sustainability of hollow and solid blocks in sub-Saharan Africa. Design/methodology/approach Indicators of stakeholder value are proposed for measuring block sustainability based on comparisons of user building value price and carbon emissions. Block manufacturing processes in Tanzania and Uganda are described and assessed in this context. Findings The results from Uganda indicate that there are economic and environmental advantages in using hollow blocks as long as they are produced to statutory compliance levels. However, where blocks are not produced to standard requirements, the results indicate that it is better to use solid blocks. This surprising result seems to indicate that blocks prepared using low additions of cement might have sufficient functional quality for simple residential building applications even though they might not meet current standard strength requirements and have low cement productivity. These results also indicate that the improvement potential indicated previously cannot be realised when hollow blocks are used for simple construction needs. Research limitations/implications Clear benchmarks for the best practical level of cement block sustainability seem to be missing. The first reasons is that the lowest acceptable compressive strength has not been defined since standard requirements might not be relevant in the studied context. The second one is that the lowest possible practically achievable cement content with acceptable cement productivity has not been established. Practical implications Understanding sustainability can be very difficult and substantial work needs to be done to introduce operational sustainability indicators. Originality/value The results contribute to the discussion of understanding, defining and measuring sustainability.