As the General Contractor, Robertson built the new gymnasium and classroom addition to the Tri-Valley Local School District High School. The additions consisted of a masonry structure, on spread footings, with a brick façade and EPDM roof. The interiors included a wood gym floor, acoustical metal decking, a cafetorium with a stage and balcony, and a new science classroom wing. The new main entrance features a radius glass cupola and an extravagant display and trophy case.