CARPENTRY & WOODWORK TECHNIQUES

Indonesia is the largest conservatory of early Muslim architectural traditions in wood across Southeast Asia (c. 15th onwards), but its Islamic heritage is also fast disappearing. Only a few wooden mosques built using traditional techniques, such as the Wapauwe mosque, still exist to this day. These mosques exhibit unique architectural knowledge in which Indic, Islamic and local Island Southeast Asian features are blended. They reflect centuries of complex cultural circulation along the spice routes.

Binding techniques

Binding techniques are used to fasten the roof on the building’s structure but also to tie together different parts of the building’s structure. The strings are made of three types of material, namely bamboo (luleba) mainly to fasten sago tree palms together to form the thatch roofing and to secure the thatch to the roof rafters, palm tree fibres (ijuk or gamutu), and less often rattan.

Luleba

Luleba is the green outer skin (exodermis) of young bamboo cane/culm taken between two nodes. This internode section is divided into strips of two or three millimeters in width separated from each other by pulling them outward. Each strip is cut at the bottom of the bamboo internode, thus separating the outer skin from the inside yellow fibres (endodermis). The fibres can be used for basketry work while the thin skin is used as a string to fasten the sago (rumbia) palms together to create the thatch roof. The extremity of the bamboo outer skin strip is cut in the shape of a needle to pierce the rumbia palms more easily.

Preparing bamboo strips.

Fastening sago palms with bamboo strips.

Strips of bamboo exodermis.

Gamutu​

Gamutu is the word used in Maluku for strings or cords made of the coarse black fibers from the petioles (leaf stems) of the aren palm or palm (Arenga pinnata), a tree native to Southeast Asia. These strong and flexible fibers make durable and resistant ropes for all sorts of constructions, including boat construction. Also called ijuk (black in Indonesian), they are also used in the fabrication of mats, brushes, brooms, and various other products. Two craftsmen are needed to make gamutu strings and ropes, one seated, the other standing behind him with a cross-shaped wooden manual spinning tool. Before spinning a gamutu yarn, the craftsmen separate the thickest fibres from a pile of tangled fibres held to the ground by the seated spinner with his feet. The softer raw fibers are ready to be spun. The seated craftsman then twists and winds the fibers into a thin continuous strand. Behind him, the second craftsman pulls this strand and rolls it up manually into a ball around the cross-shaped wooden instrument with a handle. To make a stronger rope, the yarn can be thickened by twisting multiple single-ply yarns into a double or triple-ply using a wooden block drilled with two to three holes.

Spinning a gamutu cord.

Making a triple-ply yarn with a wooden block.

Wrapping of gamutu yarn to make rope.

Restoration of the Kakehang or Customary hut for communicating with ancestors, previously a men’s house (video by Ikrima Hatuwe).

Joinery

These binding techniques, unique to this region, are clues to the antiquity of mosque building techniques. Only three types of tools were used before the introduction of chisels (pahat) in Indonesia: the adze (desel), the axe (kapak) and the knife (parang). Although carpentry experts are still uncertain about the moment of introduction of chisels in Indonesia, the oldest Eastern Indonesian building examples show that beams were indeed mainly secured together, with only a few parts (mostly the main posts) carved with these tools. Metal chisels seem to have been introduced later, probably in modern times, to allow better precision in woodworking and joinery. Joinery holes could be carved at right angles, allowing for more complex carpentry techniques, as can be seen in the mosque. Three types of joints are found in the Wapaue mosque: the mortise-and-tenon, the scarf joint, and the half-lap joint.

Three types of joints are found in the Wapaue mosque

Scarf joint.
Half-lap joint.
Mortise-and-tenon joint.
Mortise-and-tenon joint.