This paper addresses construction that takes place in or near the school building while school is in session--the most difficult kind of construction to manage. Success largely depends upon the preparation, competence, and goodwill of the school district's facility staff, the project architect/engineer, the contractor, and local school officials--and the way they all work together. In many schools, principals play a key role in the construction process. This paper presents a principal's guide to on-site school construction. (Contains 2 resources.)