Join us for our 1/2 Off Sale. Now through end of April 2020. Showroom is located at 13201 Whittier Blvd. Whittier, CA. 90602. The Mack Design Group is a design, build and bring-to-life firm that works with both residential and commercial customers. We have been blessed to work with amazing clients to create unique, one-of-a-kind architectural features, custom furniture and unique design elements – often incorporating reclaimed wood and vintage elements.