How To Install a Prehung Door

Last updated: 30 Apr 2023

Installing a pre-hung door is a fairly easy task and can be done by anyone with basic home improvement skills and knowledge. The pre-hung door comes fully assembled and ready to be installed, with the door already attached to the pre-built door frame, or jamb.

Before you commit to buying a pre-hung door, make sure you tell the manufacturer how thick your walls are. Door jambs differ between plaster walls and drywall. The jamb itself will protrude a little bit from the wall, but you want to make sure that they don’t stick out too far.

The first thing you need to do once you have the proper pre-hung door ready to be installed is to place the door in the opening. If you have an unfinished floor, you need to make sure that you fill that with some sort of space to allow the door to be opened properly and so that it is not scraping the floor.

A slab of drywall or wood will work just fine. Just make sure that the door is centered properly and that it is at the right level.

Before you begin nailing the pre-hung door in place, ensure that the door jambs are properly positioned and evenly spaced both vertically and horizontally, both on the front and back sides. Once you have confirmed the positioning, you can proceed to hold the door in place using tapered wooden shims inserted between the jambs and the door frame. This will help to hold the door in position while you work on securing it in place.

Once your door is sitting flush in the proper position, then it is ready to be nailed into place. Start with the lower side of the door where the hinges are and use a 10d finishing nail for the job. Use a hammer and nail through the jamb and part of the shim. Repeat this process on the upper hinge and both between the top and middle hinge and the middle and lower hinge as well.

Now you need to make sure that the jamb on the top of the entryway is sitting flush and is level all of the way across. If it is you can then proceed to another side of the door and use nails in the same spots on the opposite side. To complete the installation, all you need to do is get rid of the bracing in the jambs and spacers as well.

After checking the door’s alignment, you should test it by opening and closing it to ensure it functions correctly. If it does not, you may need to remove the nails and adjust the door’s position. Once it is functioning properly, hammer any protruding nails flush and trim off any excess shims.