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Formerly roof was covered with natural materials such as palm-leaves,bamboo,tree-bark,wooden shingle etc.
Above all, leaves of some palm species are most general roofing materials for houses, field-sheds and granaries.
In coastal area thatched roof of nipa-palm (Nypa fruticans) --"apong"[Iban,Bidayuh]-- is dominant and in cultivated area sago-palm (Metroxylon sagu) --"kabio"[Tagal], "mbio"[Bisaya], "balo"[Kayan,Kajang] ;the leaf of sago-palm is usually called "rumbia"-- can replace it. Sometimes some palmate palm leaves are also utilised in lowland area (Pholidocarpus majadum (supposed to be) --"rira'ng"[Bidayuh Lara,Bidayuh Selakau]--).
In highland montane area Eugeissona utilis --"kenangan"[Kelabit, Lun Bawang]--, Licuala valida --"sang""chang"[Kayan,Kajang,Berawan], "silat"[Lahanan,Sihan], "lelap"[Punan], "isang"[Tanyung], "da'un""kenyan"[Penan], "samet telava"[Lisum]-- is used for the roofing of houses and temporary sheds. Sometimes the leaves of Arenga brevipes --"darama"[Lun Bawang]-- are also available for temporary sheds but the roof of this palm cannot last long (less than one year). The same species but cultivated sugar palm (Arenga pinnata) grows blak fiber in its leaf sheath, which --usually called "ijuk"-- is not utilized as a roofing material in Sarawak although there are many fine examples of ijuk-roof in Indonesia (like Bali-, Sunda-, Batak-houses).
Generally leaflets are cut off from rachis first and folded one by one over a rod of roof-panel --"turan-sapao"[Berawan], "bangkawan"[Bisaya], "gawan"[Iban], "dalinan"[Kelabit,Lun Bawang], "bintakan"[Tagal], "riis"[Selakau]--, which is mostly made from split bamboo but split petiole of Arenga undulatifolia --"pulod"[Kelabit]-- or Salacca affinis --"birai"[Kayan],"mujan"[Kajang],"lemujan"[Penan,Lisum]-- is also available. A leaflet is so folded that one half of the leaflet may overlap the former one and is sewed each other with strips of bemban stem (Donax grandis) in lowland area whereas in highland split rattan or strips of tree-bark --"Lenaya"[Lun Bawang](not identified)--. Usually the front side of leaflet becomes inside when folded so that the back side will form the surface of roof, nevertheless in case of Licuala the front side of the leaf is always utilized. The size of complete roof-panel is about 2 m (width) by 400-900 cm (length; depends on the length of leaflet). A person can make more than 50 sheets a day and approximately 300-400 sheets are required when covering one big room of a long-house. Roof-panels are dried and then placed on roof-rafters with the tip-side of leaflet facing inside of the house so that roof cannot flutter in the wind although among Tagal and Kedayan this order is reversed. Palm roof constructed in such way will last for 4-10 years but nipa-roof is less durable because of the damage of vermin. The durability of thatched-roof depends upon both the angles of roof slope and the interval of roof-panels and of cource largely depends upon the local climate.
For the purpose of temporary shed sometimes leaflets aren't cut off avoiding the troublesome of sewing but a complete leaf of Eugeissona spp.--"nanga"[Kayan], "langa"[Kajang], "bulung"[Sihan,Tanyung], "budoa"[Sekapan], "orok"[Punan], "tajuk"[Lisum]; Eugeissona insignis has a long narrow leaflet and hard to be sewn-- or Salacca vernicularis --"lisung"[Kayan], "bo"[Sekapan], "lihum"[Lisum], "lium"[Punan], "sum"[Penan]-- is divided by two in its rachis, which plays as a role of roof batten and is bounded to roof rafters directly.
Among the former nomadic groups such as Penan, Lisum and Sihan leaves of Licuala palm are usually utilized for both roof and wall of dwelling. In this case leaflets are not cut off but palmately leaf-units are stitched with the split of its petiole so as to make one flat fan-shaped leaf, however only one or two outer leaflets are left unstitched, with which the leaf is directly tied to roof-battens. Sometimes the leaves of other palms or trees are placed over roofing. This roof is enough for the temporary dwelling of Penan, which seldom lasts more than 3-6 months. Among present semi-nomadic Penan industrial vinyl sheets are preferable for their durability, water-tightness and portability.
Imperata cylindrica --"Lalang"[Malay], "Budud"[Kelabit,Lun Bawang]-- is quite popular thatching material everywhere in southeast Asia but in Sarawak it shows only supplemental value for the lean-to of main building or the roof of granary (among Kelabit and Lun Bawang) because this material is thought to gain spreading fire easily.
Tree-bark --"kulai'"[Berawan]-- is also supplemental roofing material for temporary building among Berawan and Penan. The roof lasts more than one year but tree-bark itself is not so commonly used for roof as for wall, so I will mention about the utilization of tree-bark in the appropriate section.
Before zink-roof was introduced in the village housing wooden shingle --"kepang"[Berawan, Kelabit]-- is the most durable roofing material. Belian (Eusideroxylon zwageri) --"Terah"[Berawan]-- is thought to be the ideal wood for shingle but in highland montane region where Belian rarely occurs Geronggang (Cratoxylon arborescens) --"Labakan"[Kelabit]-- is also available.
Among Berawan the trunk of Belian is first cut off about 60cm in length and divided into two or four (depends on the size of the trunk) blocks. Then from this block wooden shingles of about 60cm long by 10-20cm wide are splitted into 2-3cm in thickness. Each shingle is made a small hole in upper end and through this hole rattan string tie each shingle to roof-battens separately so that all shingles cannot slip out in case string snaps at one point. Thus constructed shingle-roof will last 20-30 years.
At present wooden plank is the most general material for flooring, but plank was not gained easily until villagers obtained chain-saw. Formerly floor was usually made from split bambu or split nibong (Oncosperma spp.) trunk. These materials are still used for the flooring of open gallery or temporary shed.
Tree-bark was widely utilized for walling and roofing. Various trees are applicable for this purpose. Among them species of Breadfruit(Artocarpus spp.), Meranti(Shorea spp.) and Kapur(Dryobalanops spp.) are general.
Trees are first cut down and cut off by the length of wall-hight (approximately 2m). After the surface of the trunk is beaten thoroughly with a wooden mallet for about five minutes bark is stripped off from the trunk. In order to make curved bark flat tree-bark thus gained is dried for 10 days.