Students at Crosby High School and Wallace Middle School in Waterbury were evacuated for a brief period of time on Friday over structure concerns.
Crosby High School staff noticed some minor cracks in the ceiling on Friday morning and a structural engineer inspected them.
There was little snow on this section of roof, but the school inspector's office determined that the roof over the entire complex is sound and students were returned to their classrooms.
As a precaution, however, the section of the building where the media center is located will remain closed until a structural engineer can re-inspect it.
In a separate incident on Friday, staff at the Bucks+ Hill Pre-Kindergarten Annex building reported smelling natural gas in the building and found some discolored ceiling tiles.
Students were evacuated onto school buses while Yankee Gas checked and cleared the building for return.
The school inspector's office re-inspected that roof as well and found no problems, according to a release from Waterbury Public Schools.
All school buildings were inspected earlier this week for any signs of structural stress and all passed, school officials said.
The school inspector's office will continue to check on reports of cracks or discolored tiles but the district believes all schools are sound based on its inspections earlier this week.