A construction worker is in hospital with serious injuries after falling roughly four storeys at a job site in northwest Calgary.

The man. in his late 40s, was working on a building under construction at Crowchild Trail and 53rd Street N.W. around 7:30 a.m. Saturday when he apparently fell.

"Initial concerns were the significant height of the fall for concerns of internal injuries," said Stuart Brideaux with Calgary EMS. "He may have struck other building surfaces before he touched the ground."

The man's co-workers provided first aid until emergency crews arrived, Brideaux said.

Occupational Health and Safety is expected to investigate the incident.

According to paramedics, any fall of a distance over 10 feet is considered quite serious.

The worker fell roughly forty feet.