How to Install a Prehung Door

Preparing for your Door Replacement

Replacing and installing a pre-hung door by yourself is not an impossible task. It is a great do it yourself project that will save you a couple hundred dollars. If you have the desire to change an interior door by yourself then I am confident you can do it. I will give you easy to follow instructions so you can change out an interior pre-hung door in your home. When installed correctly a door will latch easily when shut and open easy to the touch.

Some tools and materials you will be needing are reciprocating saw, air nailer with 2 1/2" brad nails or a hammer and some 2 1/2 to 3" finishing nails. 3' to 4' level, cedar shims, prybar and most importantly you need a pre-hung door.

If you are completely green and are not quite sure what a prehung door is, it is a door that comes with a door jamb. The door is hinged and the hinges are screwed to the door jamb.

If you don't have any material yet and are just looking for information on this subject then the most important thing for you is to make sure you purchase a door that is the correct size. Most doors are the same height unless you have a custom opening that a special order door had to be made for. You probably don't have to worry about this. Your door should be 80" high. You can measure the width of the door by either measuring the existing door width or measuring the opening if the old door is already taken out. If you are measuring the actual old door then you will have your exact width. If you are measuring the framed opening the actual door size will be approximately 2" narrower. So for example if you measure a width of 32" then your door width is going to be 30". The same for your door height. Your opening height should be around 81 1/2 to 82" but the actual soor itself will be 80".

One more important thing to do is make sure you buy a door that has the correct swing. To find out what swing you need stand outside of the room in front of the door you are exchanging. Close the door. Now open the door. Which way did the door swing when you opened it? If the handle was on the left side and the door swung open to the right then you have a right hand door. If the handle was on the right side and when you opened it the door swung to the left then you have a left hand door.


Getting ready to install your door

Now that you have a door purchased and some tools to install it you can make sure your opening is ready. If you haven't taken out the old door yet then this is what you need to do next. The easiest way to take out an old door and door jamb is to take the casing off around the door on both sides of the door and expose the gap between the door jamb and the framed opening.

You will see some shims and nails or screws attaching the jamb to the opening. Using your reciprocating saw, cut the nails and shims so the door jamb comes free. You can take your old door off the jamb before you cut the jamb out or leave it attached keeping the door closed while you are cutting the nails.

Once you have cut out the jamb clear away all of the old material. cut off and or hammer in any old nails leaving yourself a nice surface to work with. You don't want any old material getting in the way of your new jamb and door causing you installation problems. Once you have everything cleared away it is then time to get ready to install the new door.

Pictures of before and after door installation

Old door waiting to be ripped out. Cut the door out by using a reciprocating saw and cutting between the jamb and the framing.
Old door waiting to be ripped out. Cut the door out by using a reciprocating saw and cutting between the jamb and the framing. | Source
Old door is ripped out and the opening is cleaned up from and protruding nails etc. Now ready for installation of a new door.
Old door is ripped out and the opening is cleaned up from and protruding nails etc. Now ready for installation of a new door. | Source
New door is shimmed up, levelled and nailed in place. Ready for some casing now.
New door is shimmed up, levelled and nailed in place. Ready for some casing now. | Source
This is typically what a pre hung interior door looks like. You can purchase them in wood grain and even glass insert type doors as well.
This is typically what a pre hung interior door looks like. You can purchase them in wood grain and even glass insert type doors as well. | Source

Time to Install your Pre Hung Door

Before we get started there should be some clarification on the meanings of installing a prehung door and hanging a prehung door. They mean the same thing. I don't know the exact story on the meaning of hanging a door but hanging the door probably came to be because when you install a door you are hanging the door on the hinges. So after saying that I am not sure you can really say hang a pre hung door. Anyways they mean basically the same thing, it's all about installing the door.

Now that you have an exposed framed door area and the 2 * 4's are clear of protuding nails it is time to slide your prehung door into the opening.

Take any staples or wrapping off of the prehung door that was put there to help sell the product. Take your door and slide it into the opening so there is an equal amount of space between the opening and the door jamb on both sides of the door. Next thing to do is to situate the door so the jamb is flush with the gyproc. Once the jamb of the door is flush with the gyproc you can grab your long level and place it on the hinge side of the door jamb. Level the jamb on the inside and on the outside or gyproc side of the jamb so you get it level both ways. Use your cedar shims to take up the slack between the framing and door jamb once you have the jamb where you want it.

When shimming the door on the hinge side place the shims behind the spots that your 3 hinges are on the jamb because that is where you will be nailing it. If you have the hinge side of the door jamb levelled and shimmed then now you can nail it in place, nail through the door jamb where you have the shims. If you nail where there are no shims you are going to bow the door jamb causing you problems.

Now that you have the hinge side nailed you can start on the handle or lockset side. Don't worry about the top other than makeing sure the top part of the jamb stays flush with the face of the gyproc.

Shim up the handle side of the jamb so that the door opens and closes without hitting the jamb. You will have to level the handle side of the jamb like you did with the hinge side. Shimming the handle side in 2 or 3 places will be more than enough. If you get both sides of the door shimmed and nailed and the door closes you don't have to worry about the top. Some people like to nail the top just to make the door that much more secure. I usually don't worry about it unless I have to.

Now that you have the door in place and the soor opens and closes without sticking you can install your lockset/handle.

That is about ot for installing a door. Sometimes it takes a bit of tweaking on the jamb to get the door to open and close properly. Door what you have to to make your door work properly. Sometimes a little twist on one side of the jamb and then nailed in place will fix a sticking door. Experiment if you run into problems or if you have to come back here and ask me, I woud be happy to help.

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Comments 2 comments

Grant's World profile image

Grant's World 4 years ago from Canada Author

Hi Brie,

Thank you, I am glad you found this useful.

Grant.


Brie Hoffman profile image

Brie Hoffman 4 years ago from Manhattan

Very useful, bookmarked and voted up.

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