Inadequate isolation will greatly compromise routine endodontic therapy. Loss of coronal tooth structure to caries or trauma often makes adequate rubber dam isolation difficult to achieve. This article presents some techniques for placing a buildup prior to endodontic therapy. The few minutes spent placing a buildup prior to the initiation of root canal therapy are an excellent investment in time. The time spent will be erpaid by the ease of placement of the rubber dam, the quality of isolation achieved, the reduced chance of losing the provisional restoration, and the increased quality of the completed endodontic treatment.