When Portland voters approved a $790 million bond package for school improvements in 2017 the measure included $5 million for security upgrades for most schools.

That work was originally supposed to wrap up by spring of this year. But officials now say it will take until at least the end of summer for all safety upgrades to be in place.

By fall 2019, district officials discovered they needed to install upgrades in all 88 schools, not just some, and about $4 million more to finish the work.

And because of the high demand for construction workers on capital projects in the region, officials in the Office of School Modernization said, their contractor is stretched thin and struggling to stay on schedule.

School modernization officials laid out the issues in a letter to the school board’s bond committee Thursday.

The scheduling issues began last summer, when the district found itself struggling to attract bids for its contracts.

Officials broke the district’s schools into three groups when it awarded those contracts. The first batch drew two bids for the design and construction work. The second drew one.

The district awarded the work for both batches to the same company. The contractor is currently working on upgrades in 57 schools.

The third contract didn’t draw a single bid, so officials awarded the design work for the remaining 31 separately. There’s no contract for the construction portion of those projects yet, school modernization head Marina Cresswell said.

Some of those upgrades include electronic locks on exterior building doors, video intercoms in each school’s main office and additional fencing and gates for certain sites. Officials also found certain schools lacked PA systems in hallways, playgrounds, gymnasiums and auditoriums.