In 1953, William D. Slowik joined Thomas C. Pratt and Associates. He became an associate in 1959. 10 years later he was named a partner and the firm renamed Pratt, Schafer & Slowik. Following Mr. Pratt's retirement in 1973, the firm continued to practice under the name of Schafer & Slowik - Architects.

Paul Slowik joined the firm as an intern in 1977. Following Mr. Schafer's retirement in 1985, the firm practiced under the name of W.D. Slowik & Associates. Paul Slowik became an associate of the firm in 1992. Following William Slowik's retirement in January 1995, the firm began practice under the name of Paul Slowik & Associates - Architects. As of 2010, the firm is incorporated and now operates under the name Paul Slowik & Associates - Architects, Inc.