The fire took hold of the International Conference & Banqueting Centre on Sunday, with around 70 firefighters called to tackle the flames.
It took around eight hours to get the blaze under control, with firefighters using a drone's thermal imaging to locate the main seat of the fire.
And although the blaze is now thought to have been extinguished, four crews were set to remain at the site throughout on Monday checking for any signs of hot spots.
An investigation has shown that the fire is believed to have been started accidentally, West Midlands Fire Service said.
The call came in at 10.30am on Sunday with plumes of smoke emerging from the conference centre on Fox's Lane, near the A449 Stafford Road.. Nobody was injured.
A row of fire engines could be seen on the street as crews fought the blaze at the site, voted "West Midlands Wedding Venue of the Year" last year.
A West Midlands Fire Service spokesman said: "Initial crews arrived on scene within 5 minutes. A total of 10 fire engines with supporting vehicles and officers attended.
"Our drone team also attended and thanks to the drone's thermal imaging capability, we were able to quickly identify the main seat of the fire so our crews could better locate, access and tackle the blaze.
"The fire was under control by 6pm. Several crews remain on site, including into Monday morning, monitoring the building with thermal imaging cameras and making the site safe. Four crews will remain at the scene for much of today.
"The fire is believed to be accidental with all persons accounted for."
Specialist technical rescue officers were seen cutting into the side of the building to gain access on Sunday as fire chiefs urged people to avoid the area if possible.
Meanwhile thermal images showed how the hottest part of the fire appeared to be in part of the building next to the canal.
An incident response vehicle from West Midlands Ambulance Service was also present, but everyone had been accounted for.
A spokeswoman for West Midlands Ambulance Service said: "We were called to reports of a fire on Fox's Lane, Wolverhampton at 11.21am on Sunday.
"We sent two paramedic officers and our Hazardous Area Response Team to the scene. However, there were no patients requiring treatment."
The Express & Star has not been able to reach the conference centre for comment.