In 1925, I.R. McIntosh started a business in a small shed on Garfield St, Parnell. Later that year, the business relocated to a space behind the shops at the corner of Mt Eden and Shackleton Rd. By 1927, continuous expansion required building a new 2000 sq ft factory at Mortimer Pass in Newmarket. Steady growth led to another move in 1945 to a new factory on Auburn St, Khyber Pass.
The Khyber Pass premises allowed the company to stock their Unimac brand and collaborate closely with the Grace Bros Department store, providing contemporary furniture. The Grace Bros store was situated at the corner of Symonds St and Khyber Pass Rd during the 1950s and 60s.
In the 1950s, I.R. McIntosh's two sons took on management roles within the business. K.A. McIntosh became the company manager, and T.I. McIntosh oversaw production. Under their leadership, new production techniques and modern furniture designs were developed.
In 1958, the company moved to a custom-built, state-of-the-art building on Bowen Road, Mt Wellington. The new premises drew considerable attention for its highly innovative large arched trusses that removed the need for any internal beams in the building.
Today, Unimac furniture is considered rare and sought after by collectors of mid-century New Zealand furniture.