Complex sentence: Less visible is the much larger renovation to infrastructure such as electrical, plumbing, heating and ventilation systems which improve both the safety and comfort of the school, as well as a new sprung hardwood gym floor in the large gym.
Split into simpler sentences: Less visible is the much larger renovation to infrastructure such as electrical, plumbing, heating and ventilation systems which improve both the safety and comfort of the school. We have also installed a new sprung hardwood gym floor in the large gym.