Sunnybrae started as a four classroom school, built in 1959 by Innisfil Township School Area #2 Board, at that time. The old school in Stroud on the corner of Highway 11 and Concession 10 had its two rooms full and a very unsatisfactory room in the basement. This basement was closed with the opening of the new school.
After the passing of Provincial Legislation making a township the smallest unit of administration, the Innisfil Township School Area built a six classroom addition to Sunnybrae in 1965 and sold the Thornton School S.S.#9, Holly School S.S. #12 and Knock S.S. #15. Knock and Holly were bought by the township as community halls.