Installing a Prehung Door
There are a number of reasons that a homeowner might want to install a new door in the home. Perhaps the old one is damaged, there's been a new room made out of one large room, or it's just time to spruce up the old homestead. The project is really not as mysterious as it would seem. The purpose of this article is to guide the DIY'er through the steps of installing a prehung door.
In the old days, installing a door was a bit more of a tedious process. Nowadays however, a marvelous concept has evolved: the prehung door. Prior to this, a carpenter was usually hired to do the job, which incurred a labor cost. Today, labor costs have risen but the good news is that a prehung door is easy to install for the average homeowner, saving a wad of cash. All that's needed is a bit of common sense and a few tools.
Tool and Material List
Here is what you'll need:
- hammer
- nailset
- utility knife
- 4' level
- pry bar
- prehung door
- finish nails
- a package of shims (from the door section of your home improvement store)
Door sizes are standardized. If you are replacing an existing door measure it. If this is a first time door, the carpenter will have the opening roughed out. Measure the rough opening between the studs and the height of the header. The prehung door jamb will be this size less one to two inches.
The second thing to be concerned about is the swing of the door, or, which side you want the hinges on and whether you want the door to swing into the room or out of the room. This is easy. Position yourself in the doorway on the side where, if the door were already there and closed, opening it would make it pass through you (if you were a ghost). Cross your arms over your chest. Now, as the door swings through you, one of your arms can follow its arc. Which arm? If it's the right hand arm you need a right hand swing door. Otherwise, a left hand swing door.
Installing the Prehung Door
Remove an existing door door if you have one. Take off the trim and pull the hinge pins to take the door off. Next, remove the jamb using your hammer and pry bar.
Now stand the new door assembly in the opening. The extra space around the jamb is to give you some wiggle room for getting the door assembly plumb in two directions – back and forward and side to side. Also, the top of the jamb has to be level.
Start with the butt (hinge) side of the jamb. Check to see that the header is either level or will achieve level when the door knob side is raised. If not, trim the butt side jamb. Holding the level on the inside of the butt side jamb, get it plumb both the ways mentioned above, Use the shims between the jamb and the stud (close to the butts), nail through the jamb and shims but don't sink the nails yet.
Shim under the jamb on the knob side until the header is level. Now, plumb the jamb, shim it and nail it, top, bottom, and middle. Double check all plumb and level again and set your nails.
The Final Touches
All that's left to do now is nail on the trim, putty the nail holes, and install the hardware if it's not done already. Job well done!
Kelly Smith - Kelly has over 30 years experience as a journeyman carpenter and 20 as a freelance writer and photographer.
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