The family of a 30-year-old Manhattan man who was crushed to death by an elevator in his apartment building plans to bring a wrongful-death lawsuit against the lift company and the site, according to new court papers.

The uncle of victim Sam Waisbren — whose horrific death Aug. 22 was caught on building surveillance video — filed a petition in Manhattan Supreme Court on Friday against the owners of the 23-story Manhattan Promenade tower at 344 Third Ave. and the elevator company, demanding that all evidence relating to the incident be kept safe as they prepare to file suit.

The uncle, Benjamin Waisbren — who will apply to be a co-administrator of his nephew’s estate along with the victim’s father — also wants an inspection of the elevator to be conducted with his lawyers present, the court papers say.

The family’s lawyer, Ben Rubinowitz, told The Post, “This is something that never should have happened, and this young man should never have lost his life. His family has and will suffer terribly as a result of the severe negligence and recklessness that caused this elevator accident.”

The petition names Manhattan Promenade LLC, ATA Enterprises Management Inc. and American Elevator & Machine Corporation as defendants.

The companies did not immediately return requests for comment.

The city Department of Investigation began a probe into Waisbren’s death last week after the Department of Buildings found that a safety device had been tampered with.

A funeral and burial was held for the software salesman in his home state of Wisconsin earlier this week.

Waisbren’s father, Charles Waisbren, said last week, “We are absolutely devastated.”