Cost estimates and designs for constructing a new middle school in two different locations, essential details previously unavailable, will be a focal point of discussion for the Concord School Board at next week’s work session.

Set to take place Monday at 6 p.m. at the Concord School District’s administrative offices at 38 Liberty Street, the session will feature insights from HMFH Architects, of Cambridge, Mass., on the site development costs.

Previously, the community was left with a cost estimate for a proposal that included the YMCA off Clinton Street at more than $170 million. That project has been ruled out in favor of rebuilding at the existing Rundlett site or on raw land near the Broken Ground and Mill Brook schools.

The presentation will include a side-by-side comparison of site development costs, with a breakdown by categories such as traffic improvements, infrastructure including water lines and electrical improvements and outdoor facilities like fields and classrooms. One known cost is the price to demolish the existing middle school on South Street, which would range from $3 million to $5 million.

In addition to the cost estimates, the session will outline traffic studies conducted for both locations.

At last month’s meeting, the two potential school locations — South Street, where the current middle school is situated, and South Curtisville Road, near Broken Ground School and Mill Brook School — were evaluated based on criteria such as education, safety, community impact and sustainability.

Both locations ranked nearly identical, but the Broken Ground location held a slight advantage.

In terms of education, the Broken Ground site emerged as a more favorable option due to its space allowing for future expansion and minimizing disruption to current school operations compared to the South Street parcel.

However, the school board believed it would be neither fair nor well-informed to commit to a definitive choice for the school’s location without a comprehensive understanding of the financial implications.

Having the new information on cost estimates and traffic studies, the school board is expected to decide on the school location at a special meeting scheduled for Dec. 6.

The work session will also be live streamed and recorded.

More information is available on the school district’s middle school project page.