Classification (c): Through Building Material

1) Categorization by Roofing Material:

A) Natural and Traditional Materials:

The vernacular houses make use of different materials for roofing, though pitched roofs are similar in type and technique. Though primarily traditional materials are employed for roofing, gradually new materials are explored and used with changing time. The material defines the technique used in the architecture to a certain extent.

Based on roofing materials, the vernacular architecture can be grouped under following heads:

i) Thatch andsimilar grass—The thatch is traditionally the most common and widely prevalent roofing material in the vernacular architecture of the state. The thatch variety known as sun-kher or saran kher and other wildvarieties of this grass is also used for roofing.Sometimes, the paddy stubble (nara) is also used for roofing, usually for temporary structures.

ii) Palm Leaf—The next widely prevalent variety of roofing material is the takau pat or the palm leaf. This material is mostly prevalent in upper Assam, especially among different tribal communities.

iii) Terracotta tiles or shingles—The terracotta tiles are also used for roofing, especially in the westernmost districts, adjoining the Bengal border.

iv) Bamboo—There is occasional use of bamboo or bamboo shingles for roofing. The bamboo splints are characteristically woven to make the roof. The latter two materials are occasionally used.

B) Modern Roofing Materials:

The changing situation led to the introduction of modern roofing materials in the vernacular architecture of the state. The entry of new materials has resulted in the change in the technique of roof and gradual shift from traditional roofing technique. This also compelling the services of professional craftsmen in the construction work.

i) CGI sheets—There is a gradual shift from erstwhile thatch to modern and industry produced product like Corrugated Galvanised Iron sheet or asbestos. Such a shift to modern material is due to changing socio-economic situation, which is inevitable to certain extent. Of late, even the polythene / tarpaulin are gradually seen coming up as roofing material, as a cheap alternative.

2) Categorization through Material Used for Wall:

A) Traditional Material:

The vernacular architecture traditionally uses locally and easily available natural materials for the walls. A gradual shift in the walling material is also taking place and use of modern building materials like bricks and mortar is increasing.

i) Bamboo: The bamboo is the most common and readily available material used for wall construction. There are different techniques prevalent for the construction of wall. Thus, bamboo splints (kathi) or crushed and flattened bamboos are used for the purpose. Mostly, the walls are plastered with cow dung mixed slime. However, in many cases, such walls are left un-plastered.

ii) Reed: The reed or ikara is another very popular material traditionally used in the walls. The reed is extensively used in walls of the Assam type houses.

iii) Mud or Earth: In certain pockets, soil or slime mud is used as the main material for the walls of house. This technique is prevalent mostly among Hajong, Rabha and some tea garden communities. The technique of mud walled house might be the contribution of the certain tea-tribes who brought the technique from their original homeland of Madhya Pradesh and Jharkhand.

B) Modern Material:

iv) Brick: The brick is an extensively used material for wall construction in contemporaneous time. However, brick was mostly used earlier in the Assam type houses, especially for the plinth and the lowest panels of the walls. However, the upper portions of the walls were mud plastered over the reed core, held within the wood frames. On the other hand, the walls of the R.C.C. house are entirely constructed with bricks.

3) Categorization Based on Floor Material:

Earthen Floor: The floor of the earth-fast, thatched architectures are traditionally constructed over an earthen plinth and floor.

Bamboo made Floor: The stilt architecture uses bamboo splint or flattened bamboo for the floor. Occasionally, the bamboo floor is plastered with mud as prevalent among TaiAhoms.

Wooden: The wooden planks are also used for the making the floor of a stilt architecture, especially in the stilt variety of Assam type architecture.

Betel nut tree trunk: In some non-residential stilt architecture as the byre, the betel nut tree trunks are also used for flooring.

Concrete: Due to impact of modernization and industrialization, the cement mortar made floor is in increase.