William L. "Bill" Larson, who co-founded an architecture practice that grew in 45 years to become the 500-person design-engineering firm DLR Group, Overland Park, Kan., died on June 29 in Pinetop, Ariz. He was 88. The cause of death was complications from a series of falls, says a company spokesman.

Larson was a vice president at architect Leo A Daly before founding his own firm in 1966, along with architect Irving R. Dana and engineer James P. Roubal. Dana Larson Roubal and Associates became DLR Group in 1997, five years after Larson retired. "Larson was the design force for DLR Group during its early years," says the firm. DLR Group ranks at No. 106 on ENR's list of the Top 500 Design Firms, with $110 million in 2011 revenue, including $1.5 million outside the U.S. Larson was named a fellow of the American Institute of Architects in 1972.