His father, Edward Henry Maunsell (1837–1913) was of Anglo-Irish ancestry, and was a captain in the 5th Dragoon Guards and 15th Hussars.
The next year, he became an assistant to Swiss engineer Adrien Palaz (1863–1930), professor of Industrial Electricity at the University of Lausanne, where he learned the latest techniques associated with reinforced concrete.
[1] In July 1914, Maunsell moved to R. Thorburn and Sons as their chief agent and was responsible for building two TNT factories for the British Government.
He was also involved with the concrete and steel towers for the Admiralty M-N Scheme, which were intended to close the Strait of Dover to U-boats.
[2] In 1955 he founded the business G. Maunsell & Partners in the United Kingdom which pioneered the use of pre-stressed concrete for major bridges.