The architecture of Iceland draws from Scandinavian influences and traditionally was influenced by the lack of native trees on the island. As a result, grass- and turf-covered houses were developed. Later on, the Swiss chalet style became a prevailing influence in Icelandic architecture as many timber buildings were constructed in this way. Stone and later concrete were popular building materials, the latter especially with the arrival of functionalism in the country. Contemporary architecture in Iceland is influenced by many sources, with styles varying greatly around the country. The architecture of Iceland is mainly low-rise, with many low tower blocks and two- or three-storey buildings with pitched roofs predominating. Houses and smaller municipal buildings were traditionally wooden-framed, and clad in wooden planks or corrugated metal. Often they were painted in traditional bright colours. Many architectural influences can be seen, notably in the capital, such as the once-popular Swiss chalet style. Turf houses The original turf houses constructed by the original settlers of Iceland (from the west coast of Norway) were based on Viking longhouses (langhús). The exterior turf walls were lined internally with a wooden frame, which was then paneled, with the roof resting on two rows of pillars dividing the internal space. The main room of the house was known as the skáli, consisting of a central open hearth and two raised platforms, known as set. Similar designs of longhouse have been found across Scandinavia, the Faroes and the Scottish isles, as well as Greenland. Later the houses included an additional living space, the stofa, and would be accompanied by smaller outhouses. This layout also incorporated a pantry and lavatory. Over the years, the layout became more compartmentalised, eventually to include a baðstofa (a heated sauna room). In response to the colder Icelandic climate, the sleeping area was eventually moved into the baðstofa. The design evolved as the entrance was moved between the living room and main room; all the rooms in the house were joined by a central passageway, this layout was known as a gangabær. This was possibly in response to a deteriorating climate, and as timber supplies dwindled, people went back to living in the one-room baðstofa layout. Around 1791, under Danish interest, a gable-fronted design (burstabær) was proposed by Guðlaugur Sveinsson, which became widespread in the south of Iceland where the climate is warmer. An example of this design is the Glaumbær turf farmhouse at Skagafjordur