The investigation into a Walkerville area fire isn't even over yet, but Windsor fire officials are boosting the damage estimate from a weekend blaze.

“We preliminarily had put it at $1.2 million,” said John Lee of Windsor Fire and Rescue Services. “We've upped it to $1.5 to $1.8 million, depending on contents and replacements and accommodations of the residents.”

The fire started inside 1264 Argyle Rd. six-plex early Saturday morning, according to Windsor Fire.

No one was injured in the large fire that took four dozen firefighters more than 12 hours to put out.

By Monday, heavy equipment was brought in to "de-layer" the building so the investigators from the Ontario Fire Marshal’s office and Windsor Fire could work inside safely.

The building is 105 years old and is made up of six units that share an attic. Fire officials say the day-long fire spread throughout and took over.

Lee says the building is up to code.

“We don't have the ability to update or have an owner upgrade to current standards and retrofit would not apply in this case, because they're semi-detached townhouses,” Lee said. “There’s no shared spaces between the units, so retrofit does not apply to this building.”

The Fire Marshal’s investigation is ongoing and will continue on Tuesday.