This paper aims to investigate the impact of different floor coverings on thermally activated building systems (TABS) to maximize underfloor cooling. The effects of a floor surface and room operating temperature, heat flux, thermal response time, and time constant were experimentally investigated through a side-by-side comparison between vinyl and granite floor coverings of the TABS built environment. The real-time dynamic thermal performance of TABS for different floor coverings is investigated with the aid of thermal response time (Ʈ95) and time constant (Ʈ63.8). The indoor air temperature and heat flux in the granite floor covering were maintained uniform and steady for most of the time, however, in the case of vinyl flooring, there were irregular variations and approximately similar to the outdoor ambient conditions. Also, it was observed that for the granite floor, the thermal response time is 4 h, the and time constant (t) is 2 h; however, the vinyl floor has a thermal response time of 6 h. And the time constant (t) is 4 h. Granite floor covering cooling efficiency is 64% better than that of vinyl floor covering. Therefore, for the TABS, it is desired to use granite floor covering for its lower operative temperature, maximum heat dissipation, and cooling efficiency.