Traditional mortar craftsmanship in Bagan pagodas, Myanmar: construction technique and reproduction

Myanmar’s Bagan region preserves numerous brick monuments in which lime-based mortars were used for construction and decoration, yet traditional mortar techniques and associated craft knowledge remain insufficiently studied. This study examines the functional application of mortars and stucco fabrication techniques through field investigations conducted on 80 Bagan-period pagodas, complemented by the experimental reproduction of traditional craft practices in collaboration with experienced local craftsmen. Typological analysis and direct observation showed that mortars can be categorized into three functional types: masonry, rendering, and decorative mortars, corresponding to different construction functions and stages, while stucco formation can be grouped into three methods: direct modelling in situ, prefabrication followed by on-site attachment, and composite formation over brick-built frameworks. To illustrate the practical application of these techniques, the craftsmen executed the full sequence, from material preparation to final application. Observation of the entire process showed that traditional mortar-based construction primarily relies on a lime-based binder, river sand, and natural organic additives. Builders rely on a flexible use of a generally consistent set of materials rather than fixed formulas. These findings provide a technical and methodological foundation for developing conservation interventions that are both materially compatible and respectful of the authenticity of traditional construction practices.