Pisé

The French term for rammed earth, the principal load-bearing wall construction technique of the southern Moroccan earthen vernacular. Earth is mixed with stones, gravel, and occasionally lime or straw, then compacted by hand into wooden formwork (tabut). The technique is distinct from adobe (sun-dried brick) but the two are often used together within a single structure.

The construction sequence is incremental. A pair of side boards (lwah) is fixed at the chosen wall thickness with transverse stretchers and tightened by ropes or wedges; the prepared earth is shovelled into the formwork in layers of perhaps 10 to 15 cm; each layer is rammed by wooden pestle (dabbus) until the rammer "rings"; the formwork is then dismantled, raised and re-positioned, and the next course (banchée) begun. A single course is typically 60 to 90 cm tall and 1.5 to 2 m long. The visible signature of the technique on a finished wall — slightly battered profile, horizontal lift lines, regularly spaced putlog holes, vertical joints staggered between courses — records the entire build sequence and is one of the principal diagnostic registers used by conservators to read the history of a kasbah.

Regional variation is substantial. The pisé of the lower Drâa and Tafilalt typically incorporates a high proportion of stone aggregate and relatively little fibre; the Anti-Atlas and the Mauritanian Saharan ksour use stone less and rely on tighter clay binders; the High Atlas tighremts are built in a denser, more cohesive mix using local glacial soils. The technique tolerates a wide range of soils but is sensitive to mix water content, ramming consistency, and the discipline of the maalem's team — and the difference between a wall that survives two centuries and one that fails in fifty is largely contained in those craft variables.