Stony Brook Children’s hospital will spend $55 million to expand its pediatric emergency department in Stony Brook, aimed at serving thousands more patients each year, hospital officials said.

The hospital network started construction on the addition to its existing facility last fall, but will officially break ground Friday, according to a news release from the network. Construction on the new department is expected to be completed in 2029.

The pediatric emergency department, which sits off Nicolls Road near the Stony Brook University campus, serves about 25,000 patients annually out of a 4,200-square-foot facility, according to the health network.

The new facility will be more than 37,000 square feet when completed and outfitted with 20 treatment rooms and two critical care rooms, said Kali Chan, director of medicine media relations for Stony Brook Medicine.

It will serve more than 35,000 patients per year, according to the release.

Stony Brook plans to expand its team of physicians, pediatricians and nurses to accommodate the new facility. Chan did not specify the number of employees to be hired, but said the hospital network anticipated “greatly expanding staff.”

Stony Brook opened its pediatric emergency department in 2010, and later that year officially opened its children’s hospital, Newsday reported at the time. In 2019, the hospital network opened a four-floor addition to the children’s hospital as part of a $450 million expansion that also included a cancer center.

About $21 million of the construction costs come from nearly 200 donors, including the family of Peter and Nancy Richard. Peter Richard, the former president of the P.C. Richard & Son, established the fund to expand the pediatric emergency department, according to Stony Brook University.