INTRODUCTION Analytical and documentary evidence indicates that hot-lime mortars were used in traditional construction. Tese are defned as mortars manufactured by mixing quicklime and sand, rather than the current and more commonly adopted method of combining previously slaked lime with sand. Hot-lime mortars are again being used and are perceived to have advantages over cold manufactured mortars. Little is understood, however, regarding the physical and chemical performance of hot-lime mortars. Tis paper highlights current views on the subject and considers why hot-mixed mortars appear to ofer better performance than alterna- tive lime mortars. Te potential for altered hydraulic properties, bond characteristics between the lime/aggregate interface, pore structure devel- opment, and micro-structure performance are assessed, although it is stressed that this is only a preliminary investigation aimed at stimulating debate and further research. Traditional mortar manufacture Hot-lime mortars appear to have been commonly used in the construction of historic buildings, with evidence supporting this derived from available documents and from the results of an ever increasing quantity of mortar analyses. 1,2,3 Analysis of traditional mortars indeed indicates that they tend to be binder rich (sometimes in the region of 1:1 to 1:2.5 (binder to Hot-Lime Mortars: A Current Perspective Alan Forster Hot-Lime Mortars: A Current Perspective Building Limes in Conservation larger.indd 251 31/07/2012 14:56:37