"Kang Yung Shu Uk is one of the few examples of study halls built purely for teaching purposes. Situated in the Hakka village of Sheung Wo Hang, Sha Tau Kok, it was built by the Li clan of the area in the early Qing dynasty. It began as a small private school (Sishu) for 20 to 30 pupils and was rebuilt in the reign of Emperor Qian Long (1736-1795) and renamed the Kang Yung Shu Uk. As it was constructed purely for teaching purposes, the architecture is simple. It is a two-hall building with cocklofts, providing classrooms and living quarters. It comprises a rectangular structure of green brick walls, with unfired mud-bricks and rammed earth for internal partitions. It was declared an historical building in 1991 followed by a full restoration undertaken by the Government."
Source: Antiquities and Monuments Office, "The Heritage of Hong Kong" (1992), p32.
More information on the building (and photos) can be found on the AMO website.