How To Install a Prehung Door

Last updated: 25 Jan 2022

Installing a pre-hung door is not too difficult and can be accomplished by most people who have just the bare minimum home improvement skills and knowledge. The pre-hung doors come exactly as they are labeled “pre-hung”. This means that the door comes equipped and is already hinged to the preassembled door jambs.

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.

Check to make sure that your door jambs are where you want them and are sticking out at even intervals up and down and on the backside as well. To nail it in you will first need to hold the door in a place where it is set. Tapered wooden shims should be put between the jambs and entryway to hold the door 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.

Now give the door a try. Make sure it opens and closes properly and is even all of the way around. If it is not, simply remove the nails where it is sticking out or in and adjust as necessary. Hammer the nails flush when you are satisfied and see off the rest of the shims that are sticking out.