Råmunddal Møbelfabrikk was founded in Telemark in 1936 by Sveinung Råmunddal. In 1957, when the post-war period created demand for housing, the company bought a sawmill in Lårdal and started producing houses. In 1972, the company expanded with another production unit in Seljord.
Gunnar Råmunddal took over operations and in 1973 he changed the company name to SELTOR after the first letters of Seljord, Tokke and Råmunddal. He streamlined the construction business and established the current head office in Porsgrunn in 1983. He defined the company's core values as: Security, honesty and long-term thinking, internally referred to as TÆL.
In 2007, Stian Råmunddal expanded his business to the Oslo area and with Seltor Øst, new market opportunities within residential development were identified. In 2009, Seltor Bolig was founded to manage the company's property interests. The following year, Høvik Anlegg was acquired, and in 2013, Stian Råmunddal took over as CEO and principal owner.
When Seltor Øst served large parts of Eastern Norway from Hamar in the north to Drammen in the south, it was natural to merge with Seltor in Porsgrunn to cover the entire market down to Kristiansand.
In 2015, Seltor Øst merged with Seltor, and expanded further with a separate department in Drammen. Today, the Seltor Group has offices in Oslo, Drammen and Porsgrunn.