Galliford Try inherited the late-running project when it bought Miller Construction, which won the Bangor University contract to build the centre in March 2012.
The 100,000 sq ft project was hotly contested with national contractors Bam, Galliford Try, Kier and Sir Robert McAlpine all chasing the job.
Originally the £40m Pontio project was due to stage its first productions in September 2014, but building delays saw this rescheduled to February.
The project was hit by extensive water damage requiring newly-laid floors, ceilings and walls to be replaced.
This earlier date has been moved again with Bangor University confirming parts of the complex will now open in the Autumn. The latest budget estimate also now exceeds £49m.
Professor Jerry Hunter of Bangor University said that the phased opening would be a time to trial a range of different event formats and technical configurations, before a programme for the building rolls out from December.
The new building will house the Bryn Terfel Theatre, research facilities and the students’ union.