Restoration of Historic Buildings in Zanzibar

A critical insight from this study is the identification of optimal material ratios for restoring historic buildings in Stone Town, Zanzibar. Researchers found that using locally sourced sand with a grading pattern matching the original mortar, combined with lime at a ratio of 1:3 (lime to sand), significantly improves restoration outcomes. This approach mitigates the incompatibility issues caused by modern materials, which have accelerated deterioration in previously repaired buildings. The study employed visual investigations and laboratory tests—including chemical analysis, grading, compressive strength, and water absorption—to compare historic and contemporary repair materials. While similarities were observed, the optimal ratio for repair mortar was distinct from that of original materials, highlighting the need for tailored restoration techniques to preserve Zanzibar's architectural heritage effectively.

Makunza, J. K. (2017). Restoration of Historic Buildings in Zanzibar. Tanzania Journal of Engineering and Technology, 36(1), 12–22. https://doi.org/10.52339/tjet.v36i1.475