According to its building permit, the Del Prado Apartments at 1510 E. 9th Avenue was built by A. Gruber & Sons in 1950. No architect was listed on the building permit.  A. Gruber & Sons was founded in 1935, and comprised of Albert Gruber and his sons Albert Gerald, Robert, and Donald. Denver assessor records show that Gruber & Sons was likely responsible for the construction of other mid-20th century apartment buildings in central Denver, including those at 1357 Williams Street and 669 Washington Street.