Techniques (e): Roof Construction Technique

The roof construction technique is normally similar across the number of communities living in the state. The roof construction technique demands immense traditional knowledge and expertise. After the material collection, the construction of a house practically commences with the construction of the “roofs frame”, also known as chal or roof. It is entirely made with bamboo of different variety and types. Traditionally there are two kinds of chal or roof frames-the ‘hedali’ and the “shitalichal’. The first kind of roof is made with bamboo lath which is woven in “dutia’ or jaomore”, which is the typical scheme of weaving the laths.

The second type i.e. the shitali-chal is more complex, common and preferred one for comfort and permanence. It is constructed of rua-kami i.e. with bamboo rafters tied within bamboo splinters. The rafters are usually made of full, solid bamboo pieces belonging to the special species like bijuli, ban-bijuli, makal etc., of which the banbijuli variety, growing in an open field is the best type for the purpose. The rua made from katah variety of bamboo is also regarded as good. For this, mature katah bamboo is slit into pieces, which are then rounded leaving the node-hook in one side. Sometimes, variety like bhaluka or stems of tree like ghuncha is also used for rua.

The length of the rua depends upon the proposed breadth of the house. The bamboos for the rua are cut in size and process through keeping them under (muddy) water for about 15 days. The breadth of a proposed house determines the breadth of the roof frame and the rua. For instance, if the proposed breadth of the house is12 hat (cubit length), then the each of the two roofs should be of around 8 hats breadth. Hence, the length of the ruas would be of eight hat- long.

After the preparation of rafters, two varieties of bamboo splinters (kami) viz. chal-kami and sara kami are prepared. The kami is usually made of jati or makal variety, which are hollow and moderate in thickness. For making the kami, a bamboo is preferably intersected near the node. Then the bamboo is first split into two equal halves and then, each half is slit further into number of splits of desired breath. Then the sharp edges, joint ridges, and the floppy inner layer of the splits are removed and moulded using a dao or chopper.

For the roof construction, another important and functional member is the guri and jethi. These members hold the kamis and ruas intact in their position. The guri is prepared from the strip of makal variety of bamboo. The piece is moulded round to the size of the little finger to make the guri. The guri is made slightly longer than double the length of the ruas. It is because, the guri folded in its middle to twine through the kamis. The jethi is similar in function and sometimes applied instead of guri. The jethi is a flat strip of bamboo and looks similar to the kami.

For tying of the ruas, three bamboos are first laid at distance over which ruas are laid spread at a distance of ebeget or ekjale (ten fingers breadth). Then the ruas are tied using kami while simultaneously entwine guris to hold them. In roof construction, two varieties of kamis are used. The first one is known as the sara kami, which is tied in two consecutive pairs from the both side of the ruas. Each of the rua is tied firmly to the sara kami separately using tamal, soot (cane split) or dhekialata. The sara-kamis are very crucial and functional member with which purlin is tied. Thus, after placing the ruas, sara-kami in couple are tied at a certain interval . The number of (pairs) sara-kamis in a roof depends upon the breadth of the roof frame. In a roof frame of 7 hati breadth, there apply 10 pairs of sara-kamis.

Simultaneously functional is the entwined guris that retain the kami, and ruas in-turn, in position. After tying of the four pairs of sara-kamis, the guris are intertwined to the ruas. This process of entwining the guri with kami and entire roof is known as guri kobowa. For this, two guris are first folded together at the middle by beating it slightly and then twist it through the sara-kamis of one end. Then these four guris are keep on entwining while simultaneously placing breadth wise kamis in between at an interval of ebeget. After attaching two kamis, thus two more kamis are intertwined contiguously at a gap of ebeget on one side to use them as sara kami later on. Then, after an interval of about ten ruas, one more pair of guris is tangled again through the kamis. This process is repeated to the other end of the roof. After entwining, the remaining ends of the guris are inserted back into the last two pairs of sara-kamis. Ideally, all the remaining ends of all the guris are inserted simultaneously into the sarakamis, each by one person. If the sufficient numbers of persons is unavailable, then they are inserted one by one. Thus, the kamis are placed, entwined and fixed over the ruas. The contiguous two kamis entwined to the guris are tied with another two kamis placing from the other side of the ruas. This group of kamis, consisting of two pairs of kamis, are the sara-kamis, to which each of the ruas are secured again. The kamis that remain singly on the topside of the ruas are known as the chal-kamis. The chal-kamis are very functional during the thatching of the roof. As mentioned earlier, the sara-kamis holds the ruas in place while the guris keeps the kamis intact in their position without letting them to skid. The chal-kamis, which remain without the tying with the rua, supports the thatch. Thus, after thatching of the roof, the chal-kamis prevents the slithering and dangling of the thatch below the roof.

After the completion of the securing of the kamis and ruas, there fasten the purlin (marali) with the roof, removing the bamboo placed below during the fastening of the kami, guri, and rua. In a traditional thatch house, altogether five maralis are used. Hence, there attach three maralis in one roof, while two maralis are fastened in the other. Thus, if in the first roof, the maralis of panipocha, mootpocha and mudha are attached, then in other roof only the marali of panipocha and mootpocha are fastened. The ridge bearing mudhar marali is attached at the extreme side of the roof. On the other hand, the marali of the paipocha is placed little inner side of the roof, as per the proposed aoula (eaves) of the house. Simultaneously, the marali of the mootpocha is placed at the centre of the other two maralis. The remaining two maralis are fastened to the second roof, as per the measurement of the previously tied maralis of the other roof. The maralis are placed and secured tightly near the sara-kamis. This entire process of tying of the roof and marali is known as the “ghar-ubha’ (Dev Goswami:2005).

The process of fastening of rua with kami and guri is traditionally known as chata / chatani / or chal-chata. In different stages of construction, there use various special tying knots (gathi) known as matagathi, rupahigathi, topa or topagathi, komoragathi etc. The guri is also twisted in a special manner that resembles to the twisting strands of a rope. Sometimes, guri is substituted by the bracing member of jethi, which is a flat bamboo splinter. Its inner side along with the joins are removed except the extreme one, which weave through the kamis in a wavy pattern like a thread in a stitch.

Once the binding and tying of the roof is over, the roof frame is ready for the installation and subsequent thatching. Since, the roof frames is prepared on the ground, they are lifted over to the posts using special kind of bamboo prop. However, till it is lifted and placed over posts, the roof frames is kept on ground in a special way, in a slanting position-with one side lifted few feet with bamboo props. Sometimes, the roof is thatched on the ground and then it is lifted above for installation.