The traditional Chinese kang bed is a long (2 metres or more) platform that was incorporated into home design where the winter climate is cold.
The Roman hypocaust system for heating bath houses likely owes it origins to this interesting design. The kang often took up a third to one half of a room where all household activities might occur including sleeping and working; and could also include a cookstove. In some cases, it was the entire floor of room (dikang).
Although originally made from bricks or fired clay, today concrete is often used to construct a Kang.