Analogously, the regions of Coastal and Central Alentejo are marked by traditional taipa constructions, but here these systems were improved by the addition of seismic-resistant elements. The housing units featured a rectangular plan with exterior walls made of rammed earth blocks, forming a monolithic structure, and interior walls built with the ‘gaiola pombalina’ system (Figure 69). Metal tie-rods were incorporated into the alignment of transversal walls. Moreover, the building envelope was often complemented by the introduction of buttresses, reinforced plinths or counter-arches in order to enhance the structural performance.