The Williams County Public School District No. 8 board approved moving forward with a third and final phase at Missouri Ridge School, which opened this fall.
The school was originally approved by the board in March 2017 as a middle school to replace Stony Creek Middle School, an aging facility that sat on leased land.
In January 2018, the board approved a second phase of construction as a step toward accommodating elementary school students at the site as well.
That addition is set to open in fall 2019.
The third phase, approved Monday with a 5-0 vote, will cost about $2.2 million and bring the school's total capacity to 450 students.