Yaodongs are usually carved out of a generally vertical side of a loess hill. If the side is not vertical, it must be cut vertical. The silty soil is soft and easy to dig. The cross section of a yaodong is similar to that of a cave: a rectangle in the lower part connected to a semi-circle in the upper part. The width at the floor is from 3 to 4 meters, and the highest point in the ceiling is around 3 meters or higher. The depth of a yaodong can be 5 meters or more. Windows and doors are installed at the opening of the yaodong. The inner side wall is usually plastered with lime to make it white. A platform called ''kang'' is built to be used as a bed. A fireplace is built beside the kang and the smoke and hot gas go through the built-in channels inside the ''kang'' to heat it before exiting to outdoor through a chimney.
The hill, which is practically infinite in thickness, that separates the indoor space and outdoor serves as an effective insulator that keeps the inside of a yaodong warm in cold seasons and cool in hot seasons. Consequently, very little heating is required in winter, and in summer, it is as cool as an air-conditioned room.
More elaborate yaodongs may have a facade built with stones with fine patterns carved on the surface.
Yaodongs can also be constructed with stones or bricks as stand-alone structures. Often, three or more yaodongs in a row are constructed. First, stones or bricks are used to build the arch-shaped structure, and then soil is used to fill up the external space above the arches to make a thick and flat roof.
The most famous yaodongs in China are perhaps those in Yan'an. The communists led by Mao Zedong headquartered there in 1935-1948 and lived in yaodongs. Edgar Snow visited Mao and his party in Yan'an and wrote ''Red Star Over China''. An estimated 40 million people in northern China live in a yaodong.
Golany, Gideon S. Chinese Earth-Sheltered Dwellings. Honolulu: University of Hawaii, Press, 1992.