Lahu villages vary in size, depending on locale. They range from 3 to 50 households or from around 50 to as many as 800 people. The main village, whose homesteads include a number that hold complex extended families, is often surrounded by smaller temporary hamlets that lie closer to the fields under cultivation. Most Lahu settlements are on the higher slopes of the hills and mountainsides, at the head of creeks and streams. Dai and Han lands and villages are at lower elevations where wet-rice cultivation is more feasible. Large houses are raised on stilts, with space underneath the houses reserved for domestic animals. Every house is divided into small rooms, each holding a nuclear family unit from within the larger extended family. Wood and bamboo are the most common building materials. In recent years, zinc roofing has been gradually replacing the thatched roofs, especially in the lowland areas close to Dai settlement.