Background
Nelsen was born in "Stoten" (a likely misspelling of Stoughton, Wisconsin) and went to high school in Portland, Oregon.
Nelsen was born in "Stoten" (a likely misspelling of Stoughton, Wisconsin) and went to high school in Portland, Oregon.
He worked for the, Washington firm of Heath, Gove, and Bell (see Frederick Heath (architect)) for five years until 1917 when he started his own firm. He designed at least 15 churches, 150 residences, and some of the buildings on the University of Puget Sound campus, as well as designs for several libraries. He was also an architect for some commercial buildings.
Nelsen"s works include the and the Collins Memorial Library at the University of Puget Sound.
Nelsen and George Gove are credited as the architects for the Mausoleum, which is historic landmark on the National Register of Historic Places. He did not have formal training in architecture when he went to work for Heath, Gove, and Bell, but was able to start his own firm five years later.
His first known project was a Tudor style dwelling at 2420 North. Union Avenue in and he followed it with other residential buildings in a "twentieth century period revival styles such as Tudor Revival and Colonial Revival". By the 1930s and 1940s his work became more modern and streamlined in character.
He designed a remodeling project for a Sears, Roebuck & Company
Store (1936), designed Fire Station Number.2 and Number.5 (1935) in, and after World World War II, he "continued in the Moderne vein with such projects as the Mueller-Harkins Buick Dealership (1948), the Temple Baptist Church (1949), and the Johnson Candy Company." His projects from the 1950s and 1960s include the Grace Moore Library branch (1950) and Fern Hill Library (1950) branches of the Public Library system, "an International Style addition to the main library (1952), the City Light Administration Building (1953), and a Student Center (1959)". His design for the Collins Library at United Parcel Service was completed in 1952. Nelsen was also a "coordinating architect for several fraternity buildings on the (University of Puget Sound (United Parcel Service)) campus (1961)".
Silas designed the Charlotte White Mottet Library (1930) for businessman Frederic Mottet, who "built up one of the greatest mercantile establishments in the Pacific Northwest, the Hunt and Mottet Company.
Additions and renovations were carried out in 1964, 1975 and 1989 to "expand the library, bring it up to code, and add a community meeting room.".
He was a member of the American Institute of Architects.