Investigators have determined a weekend fire at Dalhousie University was caused by smoldering embers on the rooftop.

Halifax regional fire spokesman Capt. Dave Meldrum said the blaze, which burned a hole through the rooftop of the Life Sciences Centre, was accidental. Workers using blowtorches on a new access hatch missed the ember that sparked the blaze.

The fire burned a hole through the roof, but left the majority of the building untouched.

Several buildings on the campus of Dalhousie University were also closed briefly because of a broken water main.