In precontact times Siwais lived in small, dispersed hamlets scattered throughout the region. Most such hamlets had Between one and ten houses and were located on the garden land of the matrilineage. The houses were built directly on the ground. In the 1920s the Australian administration imposed a policy consolidating the scattered hamlets into about sixty line villages in order to simplify control and improve public health. Each married man was required to build a house on piles and the new villages were located on ridges, near springs (for drinking water) and large streams (for bathing and sanitation). Many families retained their hamlet, or garden, houses and spent periods of time in both. Following the independence of Papua New Guinea and considerable pressure on resources there has been some movement away from line villages to the original hamlet sites on traditionally owned land. In most Villages there was at least one men's clubhouse ( kaposo), a much larger building where men met to talk, beat slit gongs, and organize and hold feasts. A century ago some men's houses were well decorated. Traditionally, houses have been simply made of wood, woven bamboo walls, and sago-leaf roofs. From the 1970s onward some more permanent houses have been constructed, a few with electrical generators, water supplies, or even solar power. Villages, and the population as a whole, have remained in much the same locations in historic times. New developments, including mission stations, schools, and administrative buildings, have been built outside villages and have not grown into settlements.