Troubleshooting a Prehung Door Installation
If you know where things go wrong, you can install a door that will swing the way it’s meant to for years to come.
Synopsis: Even when the factory has mounted the hinges and assembled the jambs, prehung doors still can be tricky to install. Finish carpenter Tucker Windover begins by assigning one carpenter to each side of a door. This team approach makes installation faster than two people working solo. In this article, he outlines nine steps for a basic installation of a solid-core prehung door, then gives solutions for five potential problems: (1) A bowed jamb above the top hinge creates a gap that’s too tight on the strike side; (2) the gap at the head is too tight on one side; (3) the gap at the head is too big on one side; (4) the door doesn’t close evenly against the stop; and (5) the door doesn’t close properly because the hinges are binding or because the hinge-side gap is too big.
The whole point of prehung doors is to save money on materials and labor, right? But even when the factory has mounted the hinges and assembled the jamb, a prehung door still can be tricky to install. After installing enough of these doors to spot the pitfalls, I have developed a series of techniques that explain away the mysteries and improve installations.
A prehung door assembly is really just a rectangle (the slab) swinging inside a rectangle (the jamb). I think of the door slab as a template for the jamb. The trick is to establish and maintain a consistent gap between the two, which should translate to a properly operating door.
Although prehung doors are far and away the most common setup found on a job site, there are some variations. The doors themselves may either be hollow core or solid core. Some prehungs (usually hollow core) are set in split jambs that fit together with a tongue and groove.…