Background
He was born in Skien as a son of station manager Ole Folkestad (1875–1951) and Marianne Evensen (1878–1950), and was an older brother of civil servant Anker Folkestad.
He was born in Skien as a son of station manager Ole Folkestad (1875–1951) and Marianne Evensen (1878–1950), and was an older brother of civil servant Anker Folkestad.
He finished secondary school in 1920 and graduated in engineering from the Norwegian Institute of Technology in 1924.
They resided in Bærum. He started out as an assistant in the Norwegian State Railways bridge division, then at the Norwegian Institute of Technology from 1926, then in the company Ing. Bonde & Company from 1927.
From 1937 he spent the rest of his career as co-owner of Ing.
Bonde & Company
Folkestad chaired the Norwegian Geotechnical Institute from 1953 to 1961, Byggtjeneste from 1966 to 1968 (board member since 1957) and Norges Betongtekniske Institutt from 1967 to 1970. He died in March 1976 and was buried at Haslum.
He and was a board member of Norges Byggforskningsinstitutt from 1953 to 1961.