Tongkonan are the traditional Torajan ancestral houses. They stand high on wooden piles, topped with a layered split-bamboo roof shaped in a sweeping curved arc, and they are incised with red, black, and yellow detailed wood carvings on the exterior walls. The word "tongkonan" comes from the Torajan tongkon ("to sit").

Text Source: Wikipedia

The rice-barn is something of a smaller edition of an ancestral house (tongkonan) with the significant difference that the piles on which the building rests are round, not square. Piles for the rice-barn are fashioned from the trunk of the banga palm; these trunks are so smooth that mice cannot find any foothold to climb them. The piles themselves are also called banga. As a rule a rice-barn (= alang or lumbung) has six piles, sometimes more. Beneath the alang an elevated floor is laid (sali).

To a large extent rice-barns are decorated like houses. Most of the ornaments are the same. Thus the pa'tedong motif is common on rice-barns, just as the pa'daun bolu motif is. The bottom of the sali is often decorated with carved geometric designs which are colored in with paint. Even the boards which form an extension as it were of the walls and which jut out under the sali, are ornamented with woodcarving. Like the tongkonan, the rice-barn is a status symbol. People see how wealthy a family is by the dimensions of the woodcarving of these buildings.

The primary function of the alang is the storage of rice, but the barn serves other uses as well. The sali is a work place; this floor furthermore serves as a place for people to sit or to sleep during mortuary feasts. When guests sleep there, cloths woven from fibers are draped around the banga. The sali is also where people sit when meetings of fellow villagers are convened. The rice-barn is situated invariably opposite the tongkonan so that during ceremonies the dignitaries sit in the southern part of the barn.

Source: THE SA'DAN-TORAJA by HETTY NOOY-PALM  ( http://batusura.de/lumbung.htm )