FAIRFIELD — Although they approved seed money for the Mill Hill School building project, the Board of Selectmen found the expansion project back on the agenda Wednesday — and after a long discussion, didn’t seem to have the answers they wanted.

The bonding resolution for the $1.5 million seed money for the expansion project was sent back to the selectmen because of a change made by the Board of Finance. Finance board members amended the resolution to make sure the building committee determined the cost of three different designs using three different school capacity numbers.

The selectmen in February approved the expenditure by a 2-1 vote, with Selectman Chris Tymniak voting against the resolution. There was no vote taken on the amended bonding resolution.

Now, the selectmen want to know what the overall plan is for the school district to deal with overcrowding and racial imbalance.

First Selectman Mike Tetreau said instead of finding out what the board plans to do, they have been shown scenarios the school board said are not feasible.

“We want to know what we are doing. We want to see the plan for each of the schools and how Mill Hill is best served by this,” Tetreau said.

At issue is whether Mill Hill needs to be built to 504-student capacity, 441 capacity or 378 capacity. The Board of Education has made the decision Mill Hill should be a 504-student school. That number is indicated in a long-range plan that was previously adopted by the school board. Riverfield and Osborn Hill elementary schools were expanded to 504 capacity, and an expansion is underway at Holland Hill Elementary School. McKinley, Burr, Stratfield and North Stratfield elementary schools are 504-student capacity schools as well.

School board officials have said they need to know the space available at each school in order to decide on a plan to deal with redistricting and racial imbalance.

“If we can’t build to 504, because of the site issues and the cost of a 504 on that site,” Tetreau said, “what is the back-up plan? In order to evaluate how much money you want to spend at Mill Hill, you have to know what the back-up plan is.”

Tymniak asked — as he did when the proposal first came to the board — if they were overbuilding by making Mill Hill a 504 school, or if there would be redistricting. “If you’re looking at townwide redistricting, why hasn’t that already been done?” Tymniak said. Noting the additions to other elementary schools, he said, “Things have been put in place to address overcrowding, but we haven’t used them.”

“As we are trying to take enrollment pressure off and solve racial imbalance, we need Holland Hill and Mill Hill at 504 to solve both of those,” Superintendent of Schools Toni Jones said.

“The overall plan of 504 is in the best interest of the town, the school district, the children,” Board of Education Chairman Phil Dwyer said. “Perhaps in January, I should have said the Board of Ed wants a 504 and there’s not an alternative, but our BOE has always said we will work with town officials when a financial issue is involved, and this project is no different.”

He said they should let the building committee do its job, and design a 504 school to determine the cost, “and next spring we’ll know whether the town can afford a 504 school, because the overall plan says that side of town needs capacity.”

“The Board of Ed understands the ideal size is 24 classrooms, and if we can afford it, that’s in the best interest of the town,” Dwyer said. “Plan for 504, but have the building committee look at alternatives to see what that costs us — and the Board of Finance agrees — but we continue to debate whether we should plan or pick a different number.”

The selectmen said they would prepare questions for school officials to get information they feel they need to vote on the amended bonding resolution.