Toeing and Heeling is a process to effectively strengthen a heavy, double-glazed PVC-U door to stop it from slowly bending out of shape and allowing the weighted side of the door to drop.
To ensure that exterior doors are sturdy and robust, they inherently need to be fairly heavy. When a door is opened, the entire weight of it is supported solely by the hinge on the side of the door, connected to the wall or structure of the house. Thus, there is little holding up the weight of the non-supported side of the door. It is from this inevitable feature of doors that the unhinged side of the door may begin to ‘drop’ over time.