With work on Morrison School reaching its midway point, architects are assuring the School Board that modifications to incorrectly installed roof trusses in the gym are structurally sound.“It was a minor hiccup,” said architect Paul McCall of Red Chair Architects, which designed the new school. “We don’t see any scheduling problems with the upside down joist issue.”Worries began when it was discovered crews had installed trusses in the gym area of the school upside down. However, engineers were able to modify the joists in place so they did not have to be removed.