For years, Chicago aldermen have been pleading with the Department of Buildings to assign inspectors to work nights and weekends to crack the whip on the avalanche of work being done illegally without a permit.

Their pleas have fallen on deaf ears — until Thursday.

Buildings Commissioner Judy Frydland got a rare round of applause when she made the announcement while testifying at City Council budget hearings.

Frydland praised union leaders for cooperation that made possible the “alternate shifts” — covering weekday evenings and Saturdays — at no additional overtime cost to Chicago taxpayers.

The anticipated start-up date is Dec. 1.

“Some inspectors … could work 10 a.m. to 6:30 p.m. or 11 a.m. to 7:30 p.m. … Some may want to take their children to school in the morning and want to work later or have a day off during the week for family obligations … so we’re not paying overtime,” Frydland said. “We plan to keep this going. … It’s in the union contract. … I’m very excited about it because I know there’s a lot of unpermited work going on after hours and on the weekends, especially on Saturday.”

Under questioning from downtown Ald. Brendan Reilly (42nd), Frydland acknowledged that 7:30 p.m. would probably be as late as the new shifts would run on weekdays.

“I don’t think it’ll go too much later than that because, from what I’ve learned goes out on the streets, a lot of jobs start when our inspectors get off. They start like at 4 p.m and they go until midnight. So we’ll be able to catch those, which we can’t catch now,” she said.

Reilly agreed that those doing work without permits “know exactly when your folks clock out” and when the 42nd Ward’s sanitation superintendent ends his day.

“We also have found that there’s heavy-duty construction work going on at 9, 10, 11 o’clock at night. . . . We’re lucky that the 18th police district has a couple of police officers who’ve been coached on this part of the code,” he said.

Reilly urged Frydland to work with local district commanders to “get a few more cops trained so they can help fill in the cracks” after 7:30 p.m., when the reassigned inspectors go home for the day.

“They’re happy to write the violations. It’s just a lot of ’em don’t know where in the code to find these things. If you can give ’em a cheat sheet, I bet the commanders would be willing to add that to a roll call or two,” he said.

Reilly also urged Frydland to “coach some of your fellow commissioners” at the Departments of Transportation and Business Affairs and Consumer Protection to assign their inspectors to work nights and weekends.

“There’s a lot of violations in those areas, too,” he said.

Yet another pet peeve for aldermen are vacant buildings that drive down property values, become magnets for crime and destroy the fabric of a neighborhood.

To combat that problem, Frydland has issued a request for proposals from contractors willing to “scour the city, scour court records for foreclosures” and develop a comprehensive list of all of the vacant buildings in Chicago.

“We’re very reactionary to vacant buildings…We don’t get to a vacant building until somebody complains to us about it. We don’t have a comprehensive list … where we can make them go register early and get to them before they get into such a state of disrepair,” she said. “In all the years I’ve been working with vacant buildings, I haven’t had something like this. . . . I’m hoping that, by earlier intervention, that will help.”

Frydland also disclosed that Chicago’s inundated army of 105 building permit inspectors are now equipped with hand-held tablets that allow them to enter results in real-time.

During an eight-month test that ended in September, tablets tested by ten inspectors paved the way for their collective office time to drop by eight days-per-month, officials said.

That’s because inspection results can be entered in “real-time — with “defect notices” immediately forwarded to supervisors for prompt enforcement — instead of forcing inspectors to return to the office to file reports.