A: Both! FLEX TAPE® forms a super strong bond with itself, so if you’re patching a pool it’s best to first apply FLEX TAPE® to the interior side of the pool wall and then place a second piece of FLEX TAPE® to the exterior. Remember that you should cut your FLEX TAPE® larger than the area of the leak. You do not need to drain the pool prior to applying FLEX TAPE®. FLEX TAPE® is a temporary, emergency repair and is not meant to be a permanent fix.