How to Install a Pre-hung Interior Door Properly

"Pre-hung" in reference to a door means there already is a wood frame called a casing surrounding the door, and the door is hinged and latched to it. Instead of installing an individual door by its hinges, you install the whole framed unit.

Things You'll Need

• Pre-hung door unit
• Level
• Wooden shims
• Screwdriver
• Wood screws, 3-inch
• Wood putty

Instructions

1. Stand your pre-hung door unit in a closed position in the opening.

2. Put a level against one vertical edge of the door casing. Push wooden shims into the space on the outside of the casing, between the casing and the surrounding wall, until it reads straight up and down (plumb).

3. Do the same for the other side and the top, shimming all around until the whole unit is level and plumb at all sides.

4. Open the door and test it, making sure it easily opens and closes.

5. Drive long wood screws through the casing, outward into the surrounding wood of the wall. Put the screws in pairs every 12 to 18 inches along either edge of the casing. Sink the heads completely, but make sure not to drive them so deeply that it pulls the casing out of square.

6. Use your screwdriver to extract the center screw on each hinge where it’s embedded in the casing. The screws are short, as the casing is only 3/4 inches thick. Drive a 3-inch wood screw into the hole through the casing and into the wood of the wall behind it, so the door isn’t hanging just from the casing.

7. Break off the parts of the shims that are sticking out from the outside of the casing. Press wood putty over the sunken screw heads in the casing. The door now is ready for trim installation.

References

• Ask The Builder: Installing a Door.