The faltering economy has stalled plans to move the Shriners Hospital for Children in St. Louis. Construction on the new 247,000-square-foot pediatric orthopedics hospital on Clayton Avenue was set to start in April on a six-acre site currently used as a parking lot. Shriners officials are now looking for at least a six-month extension on the construction start date, said John O'Shaughnessy, administrator of the Shriners Hospital for Children. The construction project is expected to cost $150 million and include space for 40 patient beds, four operating rooms, and 30 exam rooms.