Wat That Thong traces its origins to the Ayutthaya period, previously located along the Chao Phraya River near the Khlong Toei Port. The architectural design seeks to reinterpret traditional Ayutthaya characteristics, particularly the use of curved base lines, into a contemporary composition. The building is articulated into three parts:
1. The base, designed as a solid platform that receives the three converging street lines.
2. The middle zone, formed as outward-curving walls reminiscent of lotus petals.
3. The top, roof gable rotated 45 degrees so that the pediments align with the 84th Anniversary Great Stupa (the Golden Chedi), the spiritual center of the temple housing the Buddha’s relics.
The proportions of these three parts are inspired by the principal Buddha image of Wat Na Meru from the Ayutthaya period. The roof is clad with bitumen on OSB board and finished with folded copper shingles in a diamond pattern. Each pediment niche features a copper repoussé Buddha figure, raised relief from the exterior and low relief from the interior, crafted using an electrolyte technique to achieve an exceptionally thin surface. The Buddha motif, Ayutthaya (U Thong) style, is based on the first principal Buddha image of Wat That Thong. These figures alternate with triangular orange-peel surface glass windows: 21 units on each side, totaling 84 units, symbolizing the 84,000 Dhamma teachings. All 84 figures are visible simultaneously from inside through the central vertical opening, which functions as skylight. During the day it introduces natural light; On the other hand, at night, LED candle-like illumination casts traditional shadowed reliefs of the interior low-relief forms. Ventilation fans are installed at the roof to facilitate heat stack effect from beneath the roof to the outside.