Career
Treganza trained at a technical school in Healdsburg, California and then took architectural classes under William South. Hebbard. He was later employed in San Diego, California for Hebbard"s firm he had formed with Irving Gill (Hebbard & Gill) where he learned contemporary architectural styles, including modern, craftsman and prairie school styles. Treganza and Ware were prolific designers during a building boom in Utah.
Treganza has many of his architectural designs listed on the United States. National Register of Historic Places with his design partner Ware.
In 1926 he moved with his family to Florida for a short time before returning to Lemon Grove, California. In California, Treganza continued to design many civic buildings and homes in the Spanish revival style such as the MacGregor house in Lemon Grove and the former San Diego Police Department in San Diego.
Treganza was an avid birder throughout his life. The sub-species ardea herodias treganzai, commonly known as the "Treganza blue heron" was discovered by Treganza on Antelope Island in the Great Salt Lake in 1907.
Treganza, with his family amassed a collection of 30,000 bird eggs from around the world that have since been portioned out into various museums.