Part of the ceiling at the £28 million North West Community Campus, which is set to open next month, was brought down into the new staffroom at the weekend- just hours after the building was given a completion certificate by the council.
Photos circulating on social media show joists, panels and plasterboard lying on fixtures and fittings.
However, construction company GRAHAM say it was a controlled event by their workers after a leak was spotted.
A spokesman said: “During standard testing toward the completion stage of construction a leak occurred within the staffroom area.
“This testing was carried out in the evening and in a controlled environment supervised by experienced members of GRAHAM’s staff.
“The matter was identified and isolated and acted upon immediately.
“The weight of water over a period of time saturated ceiling tiles and caused sagging and superficial damage.
“GRAHAM took the decision to remove the ceiling completely in this area to ensure full and robust rectification works could be undertaken.”
Following the incident, some parents are now refusing to send their children there.
Concerned mum Suppat Ward says she is unconvinced by GRAHAM’s explanation, and has been left fearful.
She said: “Why test the roof when there was furniture in the room they were testing?
“Whatever reason the council are giving for the roof collapsing, it will not make me change my mind to send my children there now. I plan on moving them to another school.”
Responding to concerns, Dumfries and Galloway Council said: “GRAHAM applied for a full habitation certificate on Friday.
“The leak was not in relation to the structure of the building. The ceiling is not a structural item as it is an internal plasterboard ceiling.
“It is common for testing to continue within the building until it is handed over by the contractor.”
The new school is set to house pupils from Lochside and St Ninians primaries, Maxwelltown High and Langlands School.
*See the Dumfries Courier for the full story