Batak architecture refers to the related architectural traditions and designs of the various Batak peoples of North Sumatra, Indonesia. There are six groups of Batak who speak separate but related languages: the Angkola and the Mandailing to the south, the Toba, and to the north the Pakpak/Dairi, the Simalungun, and the Karo. While the Batak groups are now Muslim or Christian, elements of the ancient Batak religion remain, particularly amongst the Karo.
The architecture and village layouts of the six Batak groups show significant variety. Toba Batak houses, for example, are boat-shaped with intricately carved gables and upsweeping roof ridges, and Karo Batak houses rise up in tiers. Both are built on piles and are derived from an ancient Dong-Son model. The bale ("meeting hall"), rumah ("house"), and sopo ("rice barn") are the three main building types common to the different Batak groups. The rumah has traditionally been a large house in which a group of families live communally. During the day, the interior is shared living space, and at night, cloth or matting drapes provide families with privacy. Most Batak now live in modern homes, and many traditional houses are abandoned or in a poor state of repair.
The Toba and Karo Batak live in permanent villages and cultivate irrigated rice and vegetables. On the other hand, the Angkola, the Mandailing, and the Pakpak practiced slash-and-burn agriculture which required frequent changes of location and their villages were only semi-permanent.
Irrigated rice cultivation can support a large population, and the Toba and the Karo live in densely clustered villages, which are limited to around ten homes to save farming land. Unirrigated slash-and-burn agriculture supported smaller villages with only several houses. All villages are located near watercourses and fields. Internecine Batak warfare before the twentieth century saw villages sited in easily defensible positions. High bamboo stockades fortified Pakpak villages and barriers of earthen ramparts with bamboo fencing and trees.
Each Batak group has its own rules and traditions guiding village layout. Toba Batak houses are laid out side by side with their front gables facing the street. Traditionally, each house would have had a rice barn granary opposite which would a complementary row in the village. The street formed between the row of houses and the row of granaries is known as the alaman and is used as an area for work the drying of rice. The Mandailing also build their houses in row, however, like the Minangkabau the front gable faces the neighbouring house's rear gable. The Karo and the Pakpak do not lay their houses out in streets but around a village focal points such as the meeting hall (bale) or rice pounding house (lesung).
Toba architecture 
Batak Toba culture centres around Lake Toba and the sacred island of Samosir that lies within it. Jabu is the Toba language word for rumah adat. The houses are made up of three sections. A substructure of large wooden pillars resting on flat stones (or concrete nowadays) protects the structure from rising damp. Some of these pillars support longitudinal beams known as labe-labe, which run the length of the house at head height to carry the massive roof. Other pillars carry two large beams with carved singa heads which, with two lateral beams mortised into them, form a great ring beam bearing the small living area. The substructure is strengthened by beams mortised into the piles which double as night stalls for cattle. Walls are lightweight and lean outwards and provide additional stability to the structure. The wall and the wall plate supporting the rafters hang from the labe-labe with rattan cord, while the base of the wall sits on the ring beam. The rafters spring from the wall plate and are angled outwards producing the roof curve. In lieu of horizontal bracing battens, diagonal ties—running from the middle of the labe-labe to the gable ends—provide reinforcement.
The large steeply-pitched saddle back roof dominates the structure. The roofs are traditionally thatched, and with no internal roof trusses they provide a large internal space. Sharply projected triangular eaves and gables overlap all around the substructure. The front gable extends further than the rear gable and is finely carved and painted with motifs of suns, starts, cockerels, and geometric motifs in red, white, and black. The rear gable remains plain.
The living area, which is supported by lateral and transverse beams, is small and dark. Light enters through a small window in each of the four sides. The inhabitants spend most of their time outdoors and the house is largely used for sleeping. An attic space is provided by a flat wooden ceiling over the front third of the living area. Family heirlooms and sometimes shrines are stored here. Traditionally, the Toba Batak would cook over a hearth at the front of the living room making the living area smoky. With recent changes in hygiene practises, the kitchen is now often in an extension at the rear of the house.
The original Toba Batak houses were large communal houses, but these have now become rare, with most houses now built in the ethnic Malay style with both modern and traditional materials. While more spacious, better ventilated, brighter, and cheaper to build, the jabu is considered more prestigious. Where jabu are still lived, they are generally smaller single-family dwellings. Whereas previous versions of the jabu were accessed through a trap door concealing steps in the floor, times are now less dangerous and more convenient wooden ladders at the front of the house provide access.
Toba Batak rice barns (sopo) were built in a similar style but are smaller than the jabu. Rice was stored within the roof and was supported by six large wooden pillars, which carried large wooden discs to prevent rodent ingress. The open platform beneath the roof structure was used as a working and general storage space and as a sleeping place for guests and unmarried men. Rice barns are now rarely used for grain storage, and many have been converted to living areas by walling off the open-air section between the sub-structure and the roof, and adding a door.
Karo architecture 
Karo rumah adat are longhouses, for multiple family occupancy, up to twelve families in some areas, though usually eight. A Karo longhouse would be large, in order to accommodate so many families, and is built on stilts. 
In order to choose a suitable site for the house, the guru (witch doctor) would be consulted, who would determine whether the land was bad or good. A plot would be staked out using coconut fronds, and other villagers would be given four days to object to the proposed construction.
After the four-day period had elapsed, a hole was dug in the centre of the plot, into which was placed a knife, betel leaf and rice. The guru and the kalimbubu and anak beru would perform rites to determine that the ground was suitable.
After the site was ready, a seven-day ceremony was performed, consulting the spirits of the forest (for wood) and arranging payment for the craftsmen responsible for creating decoration of the house.
All the occupants of the village would then erect the pillars supporting the house, after which they would eat together.
The colours used in Karo designs are red, white and black. The red signifies a zest for life, a 'get-up-and-go', the colour seen in traditional clothes used in weddings, black the colour of death, man's ignorance of Dibata's (God) will, and white, the colour of God's holiness.
Ornamentation is very important in Karo houses, with Buffalo horns an essential decoration of the rumah adat, and two white-painted horns are mounted on each end of the roof (the mounting is done in the night, so nobody sees), using both male and female buffalo. Ornaments in Karo houses served traditionally to protect the residents from evil spirits, and to demonstrate the status of the owner. With the fading of traditional religious beliefs (permena), they are now largely decorative and a reminder of past cultural traditions.
Ornaments of Karo homes are found in three ways:
- The house is decorated with braided bamboo in a variety of geometric designs. The geometric designs have been classified into seventeen types, each having special magic properties, such as the Tupak salah Silima-lima (five-pointed star), symbolising the merga silima, and deterring those who would try to upset the integrity of it. 
- The kitchen is decorated with carvings
- An intaglio carved gecko protects the occupants from evil spirits
The roof of the Karo house is different from other Batak peoples, being a hip roof. The roof is the dominant feature of the house, sometimes being as tall as 15 metres high, against the supports and walls, both around 1.5 metres each.
The most basic house, known as rumah beru-beru, has a basic hip and saddle roof. The rumah tersek has a double-storied roof with a saddle roof on top of the lower part. This improves ventilation in the house, reducing the impact of cooking smoke. A house with four gables, known as a rumah si empat ayo has two saddle roofs crossed at right angles. In some cases an anjong-anjong, or miniature house, may be placed atop the house for further decoration
Internal organisation 
The Karo adat house has two entrances, on the north and south ends, with a small terrace (ture) on each and stairs leading up to the house. The ture serves as a place to bathe children and to chat at night.
The traditional eight-family Karo longhouse contained four kitchens, each shared between two close families, and containing two stoves each. The stoves was made using five stones as a symbol of the Karo merga silima (five Marga).
The house was structured so that the pengulu (leader) of the house occupies the front-left room, with his sembuyak (parents) in the room to the right. In a mirror image, his anak beru and kalimbubu would occupy the corresponding rooms entering from the rear of the house. The four rooms in the middle of the house were of lower status and each contained a kitchen, which was shared with the rooms on their outside.
The keben or rice barn is an important part of Karo culture, since rice represents a store of wealth, and the size of the keben therefore demonstrates one's wealth.
See also 
- Dawson, Barry; Gillow, John (1994). The Traditional Architecture of Indonesia. London: Thames and Hudson. pp. 35–36. ISBN 0-500-34132-X.
- Dawson, Barry; Gillow, John (1994). The Traditional Architecture of Indonesia. London: Thames and Hudson. pp. 36–39. ISBN 0-500-34132-X.
- [Fungsi Dan Makna Ornamen Rumah Adat Karo : Kajian Semiotik http://repository.usu.ac.id/bitstream/123456789/19434/5/Chapter%20I.pdf]
- Les Batak: des hommes en Indonésie : un peuple de l'île de Sumatra
- Kinship, descent, and alliance among the Karo Batak - Masri Singarimbun
- Breath becomes the wind: old and new in Karo religion
|Wikimedia Commons has media related to: Batak vernacular architecture|