Among the tools commonly used in rice terrace building are spade (gaud), crow bar (dohag/balita), and bolo. Wooden pestles are also used especially in tamping soil or clay during back-filling of stonewalls and dike construction. On the other hand, building materials are composed of stones, rocks and soil. Two kinds of stone are used on terraced walls.
One is fired, split sandstone (piningping, pinhi’) from big boulders of rocks and the other is river-washed cobblestone (muling). One stone is systematically installed on top of the other with the use of soil and small stones as bonding and fill materials.
Soil bonding principles are observed when restoring eroded earthen walls or repairing cracked walls. The restorations always start by excavating the damage up to the portion unaffected by the cracks. Restoration methods are applied according to the condition of the damage (Guimbatan:2003).
Stonewalling and Backfilling: Tuping and Tabab
The foundation stone (gopnad/dalinat) is laid on the excavated slope and filled back with soil. The second stone (aldoh) is laid on top of the foundation stone followed by subsequent layers of soil. Angular stones of longer dimensions are laid as headers and stretchers.
This helps develop transverse strength trough the wall. On the other hand, elongated stones are laid tilting back into the terrace body with the heavier and higher end facing out (Guimbatan:2003).
If there is an internal water source (utbul), runo canes are laid from the spring to the outer wall supported by coarse fill of small stones (gangal), and covered by gravel fill (adog). Then, hard packed earth is laid on top of the adog.
The stones are filled with soil and tamped with a wooden pole or a pestle to make it compact. Wedges and chinking stones are also generously used as fillers (tabab). The care with which terrace fill is packed behind each vertical rise of stone walling contributes heavily to the lasting quality of such workmanship.
When the desired height of the stone wall is reached, backfiling and tamping are done vigorously until the soil is dense to make a hard earth fill (haguntal).
The area is leveled and the terrace bed is filled with soft and thoroughly worked clayey topsoil (luyok) to a depth of at least 20–30 centimeters. The clayey surface is smoothened and inclined slightly downward toward the uphill side margin to safeguard the loss of pond water (Guimbatan:2003).
A dike is constructed at the outer rim of the rice paddy. This is done by laying of soil to build the bund, moistening the bund, and plastering the bund with clayey soil with a paddle spade and then pressing it into place by the heel of the foot.
In drier terraces, the outer margin may be drained for the seal at the rim to be pounded with wooden pestles (Conklin:1980:19).
If sufficient clay is available, the clay is thickly plastered on the top and sides of the dike with paddle spade and pressed into place with rapid foot action.
This coating helps reduce water seepage, retard weed growth on the dike, and raise the dike to the desired level (Conklin:1980:19). Dikes are provided with at least one spillway each.
Then, the pond is filled with water. Some of the dikes that are used as heavily traveled footpaths are overlaid with stepping stones.