The ancient Vihara of Wat Lai stands as a prime illustration of early Ayutthaya architectural style, noted for its elongated hall and a foundation adorned with a single-tier inverted lotus motif. A defining characteristic of this period is the absence of windows; instead, the walls are punctuated by vertical slits or ventilation gaps on both sides to facilitate light and airflow. This design was common before the reign of King Narai the Great. Moreover, the roof structure relies on interior pillars for support and features an open front porch. The robust brick-and-mortar construction showcases the building techniques of an era that emphasized durability and simplicity, while preserving the sacred ambiance of a Buddhist sanctuary.