YARMOUTH — Architects expect construction of additions and renovations at each of the town’s four schools to begin by October.

That means the Planning Board has a tight timeline for reviewing and approving the plans, which include several “meaningful and significant changes to school infrastructure,” board Chairman Tom Federle said.

Wendi Holden of Harriman architects said earlier this month she hopes to receive final site plan approval for both the Rowe Elementary and high school projects by June 26, and final approval for Yarmouth Elementary and Harrison Middle schools by Aug. 14.

Yarmouth voters approved borrowing $52 million in June 2018 to fund the expansions and improvements.

The most expensive and significant changes will take place at Yarmouth Elementary, where a two-story, 11-classroom addition will be built.

There will also be specialty spaces for art and music, along with classrooms specifically designed for English language learners, foreign languages and technology instruction.

The project is estimated to cost $27.3 million and also includes a new full-sized gym and a new, more secure front entrance.

The most significant change, however, will be making room for the fifth grade, which is now housed at Harrison Middle School.

The Harrison project is expected to cost nearly $5.2 million and includes three new classrooms and instructional support spaces for specialized math, literacy and English language learner programs. The middle school will also get a new entrance lobby, Holden said.

The high school project is expected to cost $12.7 million, according to materials Holden provided to the Planning Board in mid-March.

Major changes at the high school include creating a new main entrance and adding nine regular classrooms, two science classrooms, a learning center and a robotics room.

The Rowe project includes four new classrooms, a staff workroom and specialized spaces for math, literacy and English language learner instruction. In addition, the nearly $6.7 million addition also includes workspace for a school psychologist and an instructional strategist.

Holden said the Rowe project would likely take 12 months; the middle school would take 10 months; the high school would take 16 to 18 months, and the elementary school project would take 24 months.

Kate Irish Collins can be reached at 780-9097 or kcollins@theforecaster.net. Follow Kate on Twitter: @KIrishCollins.