Nestled in the village of Okawville in southern Illinois, the West Washington County School District occupies a 37,000-square-foot campus, newly completed in 2013. It’s a modern K-12 school building constructed around a lovingly restored, 1950s-era gymnasium where generations of “Rockets” athletes have chased victory — an ideal blend of historic and contemporary. But after five years in the building, school administrators grew concerned about problems with the HVAC system.