Boston inspectional investigators are trying to figure out why a roof collapsed on a five-story building in the North End on Thursday morning.

The building was vacant and under construction but the contractor says no work had been done in at least two years.

People inside nearby buildings were quickly shuttled out the door after the roof at 43 Fleet Street came crashing down around 10 a.m. Twelve residents were displaced by the collapse.

Mike O’Brien heard the collapse from his building across the street where you can see some of the areas that collapsed down. Rachel Bieling and Charlotte Simmons were working from home in one of the neighboring buildings that were evacuated. “Firefighters came up and they were like we are evacuating your building. You guys need to come down. So we came into Starbucks and luckily grabbed our laptops,” said Bieling. “At least our building itself was not damaged and hopefully it is not going to be too bad and we will be able to go back in today or later or tomorrow,” said Simmons.

Boston Fire Department shared drone footage of the damage, displaying a gaping hole in the roof of the North End building.

Further inspection showed the integrity of the roof and parapet wall seemed to be compromised because of the increased weight from years of water build-up and other factors, said Boston Inspectional Services.

Fire investigators say they are also working on a specific cause. “A lived-in building when you see problems you deal with problems. If the building is not lived in problems can get worse and that is likely the situation here,” said Deputy Fire Chief James Greene.

The residents who were evacuated were allowed to go in later in the day to retrieve their belongings.

The Building Commissioner has asked the property owner to hire a licensed engineer and submit mitigation plans and drawings to the department. Additionally, the owner was ordered to hire a company to stabilize the building.

A collapse zone was established around the perimeter of the building.

This is a developing story. Check back for updates as more information becomes available.

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