Additional building programs have been authorized by the congregation at various times since the completion of the new church. With the purchase of buses to make to possible for more children of the congregation to attend the Hastings Street Christian School, the school soon became overcrowded. Therefore, it was decided in 1955 to proceed with the construction of a new school on a four-acre site on Plymouth Avenue to be purchased from Mr. and Mrs. Matthew Stoutjesdyk. The new school was to have six classrooms and an all-purpose room. In that same year the church parking area was expanded by the purchase of two lots facing Union Avenue.
In 1960, a new parsonage was built on Romence Street.
Enrollment in the Plymouth Christian School continued to grow until the building became filled to capacity. As a result, an addition was built in 1963 consisting of three classrooms and some smaller rooms.
Increasingly, parents began to realize the importance of providing a complete elementary and secondary curriculum for their children. This strong commitment to Christian education manifested itself in the purchase of a vacant school building on Ball Avenue from the Public school system. The elementary was transferred to this newly purchased building and the high school expanded by one grade per year. The full Kindergarten through grade 12 curriculum was offered in the fall of 1983.
During the early years of Rev. Lamain’s ministry in Grand Rapids, the congregation grew rapidly. By the late 1960s membership had exceeded thirteen hundred. A church addition was dedicated in 1974.
Scores of immigrants settled in the North American churches during the 1950s and 1960s. This placed increasing demands on our minister to attend to both the material and spiritual needs of several shepherdless flocks scattered throughout the United States and Canada. In addition, Rev. Lamain provided leadership to the denomination by serving on several denominational committees, as editor of the Banner of Truth, by writing edifying literature, and, near the end of his life, as theological instructor. For more than thirty-seven years the Lord granted Rev. Lamain to labor faithfully in the midst of the North American congregations, serving as a blessing for many.
On November 12, 1984, Rev. Lamain was taken to the hospital for a minor operation. After three days he could return home, but though he had planned to preach again the next Sunday, he felt too sick to do so. His sickness worsened. On Thursday evening, November 29, he asked his oldest daughter to read Hebrews 12:1-13 for him. A few hours later, in his sleep, the Lord allowed His child and servant, William Cornelius Lamain, to depart in peace according to His Word. May he being dead, yet speak to us.