Chong Partners Architecture, a San Francisco-based firm with 2006 revenue of $42.4 million and nearly 200 employees, is the latest North American acquisition by Stantec, the publicly-traded Edmonton, Alberta–based engineer-architect. Terms of the transaction, completed yesterday, were not disclosed.

“The addition of Chong Partners is a significant step towards building a national architecture presence in the United States similar to what we have been able to achieve in Canada,” Tony Franceschini, Stantec president and CEO, said in a statement. He added that Chong offers significant hospital and health care facility design to Stantec’s capabilities. It also expands the size of its North American architecture practice to 700 people and its California staff to 850. Stantec has roughly 6,500 employees and projected 2007 revenue of at least $600 million.

Published reports hint that the sale follows two years of corporate difficulty for Chong following the defection of four top owners to start a competing firm.

A version of this story first appeared on McGraw-Hill Construction’s enr.com.