Installing a Prehung Door

This story shows how to install a prehung door.


A prehung unit takes a lot of the demanding precision work out of installing a door. Hinge mortises and holes for the lockset and strike are already cut. But you still need to work carefully for best results. Check that the rough opening is fairly square and plumb. As you work continually double-check the unit for square and plumb. Take the time to fix mistakes as they occur rather than hoping they will be hidden by the next step.

If you are hanging a door in an older house, keep an eye on the big picture. Before setting the nails step back and look at your work. If the wall or floor is off level or plumb, you may want to align the door frame at least a little bit out of plumb in the same direction so it blends in. For example, if the wall leans slightly, match the jamb to the wall. It won't be noticeable as long as the door doesn't lean enough to open or close by itself.

Prestart Checklist

About 2 hours per door

Level, circular saw, layout square, hammer, nail set, utility knife

Cutting, driving nails, checking for plumb

Frame the doorway and apply drywall to both sides.

Prehung door to fit the opening, shims, 16d finishing nails, 8d finishing nails

Step 1

Tap out the hinge pins with a screwdriver and hammer. Remove the door. Slip the frame into the doorway and check the head jamb for level. If it isn't, shim under the jamb on the low side. Measure the shimmed space, then remove this amount from the opposite jamb.

Step 2

Check that the jack stud on the hinge side of the opening is plumb. Also check to see if the wall leans. If the jack stud is plumb, nail the jamb directly to it with 16d finishing nails, two below each hinge and two near the center.

Step 3

If the hinge-side stud is not plumb, nail either the top or bottom, whichever is closer to the center of the opening. Insert shims at the opposite end to plumb the jamb. Below the shims, drive two 16d finishing nails just far enough to hold the shims and jambs in place. Adjust shims if necessary.

Step 4

Before setting nails, check that the hinge jamb is centered across the wall thickness. A typical jamb is slightly wider than the wall thickness to allow for irregularities in the drywall. If adjustment is necessary, pull the nails, protecting the jamb with a scrap under the hammer.

Step 5

Put the door back on its hinges and swing it closed. Insert shims between the jamb and the stud about halfway between the hinges and adjust them until the gap between the door and jamb is equal from top to bottom. Open the door and drive two 16d finishing nails below the shims.

Step 6

The strike side of the frame is also nailed in three places: top, bottom, and middle. Insert shims and adjust so the gap between the door and the jamb is even, top to bottom. Nail the jamb in place with pairs of 16d nails driven just below the shims.

Step 7

To get the stops in the right position, screw the strike plate to the jamb, slip the bolt into the door, and screw it in place. There is no need to install the entire lockset at this time.

Step 8

On many prehung units, the doorstops are only temporarily attached, to be mounted permanently after the unit is in place. Pry the stops free. Close the door and hold it tightly against the strike plate. Nail the stops in place while holding them against the door.

Step 9

If the door and jamb are to be painted, use a matchbook cover as a spacer between the door and stop as you nail the stop in place. This allows for the thickness of the paint on the various surfaces.

Step 10

When you are satisfied with the fit of the door within the frame and the frame within the opening, drive 8d finishing nails through the jambs and shims to lock the shims in place. Cut off the shims with a utility knife or handsaw.

Step 11

As a final step, replace two of the screws in each hinge with screws long enough to reach into the jack studs. The door hangs from the jack studs, not just from the jambs.

Comments (4)
rdr531yahooco wrote:


3/26/2015 11:46:05 AM Report Abuse
Add your comment

You must be logged in to leave a comment. Register | Log In
Find a Pro

Get free quotes from prescreened professionals in your area.