Ovando ordered the construction of houses and buildings to be no different from the good standard Castilian buildings. The result was a striking contrast with thatched houses, so-called because of the materials and wooden posts used in walls and thatched palm fronds. ￼These houses were built by the Indians as close variants to the native huts required by the new settlers, who had the absolute need of accepting their new homes, while other circumstances would enable them to build stone houses. The use was generalized for houses built using solid materials, contrasting the modest houses built using slats, poles, straw and palm fronds, which continued being called huts because they really were variations, featuring few modifications to indigenous huts. ￼The stone houses would later be pisé-based (a building system featuring rammed earth in a mold), thereby forming their walls using structural elements such as local limestone bricks, produced in makeshift brickworks during the early urbanization process. In reality, the houses were very solid, generally raised on two levels. Several townhouses for residential purposes and others for rental purposes were also built. ￼The latter houses, of the eleven Ovando two-level residences were less ostentatious, but formed the set of Calle Las Damas and its cornering with Calle Las Mercedes. This was the first conurbation of America developed by Europeans. The first stone houses were built simultaneously. Both continued to be built on the continuation of Calle Las Mercedes, towards the intersection with Calle Real de las Canteras, known today as Isabel La Católica. It was a known intersection known as Las Cuatro Calles, where the urban residential and commercial center was established.
The Calle Las Damas remained as administrative pole, with the enclosure of the Fortress and the House of Trade, then Palace of Governors and Royal Justice Palace (*Las Casas Reales). Meanwhile another pole was forming around the Plaza Mayor, and in the vicinity were raised the Cathedral, the Town Council, the Royal Prison and other buildings, hence defining the city with the bipolar scheme that many urban historians and analysts have warned about.
Las Cuatro Calles, a boisterous and popular site, began developing during this first decade, featuring four pairs of houses, owned by mariner Alonso Pérez Roldán in Calle Las Mercedes, and seven pairs of houses, property of don Francisco de Garay, in the Calle Real de Canteras (today the Isabel la Católica), facing the town market. ￼Garay continued building other houses in the Calle de la Herrería (today Las Atarazanas), facing the developing site for the future Viceregal Palace, which would start after the arrival in 1509, of the new governor and viceroy don Diego Columbus, whose house, called the Columbus Palace (*Alcázar de Colón), broke the original city outline and scheme with its privileged location, amplitude and remarkable features. The development of other stone houses was mainly due to affluent personalities. Fernández de las Varas, Francisco Tostado, Juan de Rojas, and Del Viso and other powerful merchants and influential officials, who were able to settle per their possibilities, in this type of house. The majority of the population however stayed in thatched cottages, in the huts that kept their presence within the city, sited always at the border of the urban development. The city walls were finished quite tardily in the late 18th Century, but the conurbation did not occupy the defined urban layout. This took place sometime later, about a century after, when in the late 19th Century, official ordinances were issued that required for the new houses to be solid constructions, featuring brick walls or laminated wood panels, and their ceilings to be galvanized sheets over wooden structures, leveraging the commercial movement and industrial material boom imposed by the 19th century.