In 1925 I.R. McIntosh commenced business in a small shed in Garfield St, Parnell. Later that year the business moved to a space behind the shops on the corner of Mt Eden and Shackleton Rd. By 1927 continual expansion meant building a new 2000 sq ft factory at Mortimer Pass in Newmarket. Steady growth meant another move in 1945 to a new factory Auburn St.
By the 1950s I.R. McIntosh's two sons became involved in management of the business. Under their guidance new production techniques and forward looking modern furniture designs were developed. Today Unimac furniture is a rare find and good examples are coveted by collectors of modernist New Zealand Furniture.