How to Replace Your Door

Replacing a door is not difficult, and it can be accomplished with a few basic hand tools, a reciprocating saw and a good level. The first step is to select the new door, preferably of the same width and height of the door that’s being replaced. This will avoid a need to re-size the opening where the new door will reside.
The easiest type of doors to install are pre-hung in a wood jamb, and pre-drilled for a lock. Others are independent doors that have a primer coat, are mortised for hinges and pre-drilled. Finally, there are raw doors that are unfinished and require routing for hinges, as well as drilling for the lock set
Raw doors require skill and expertise to size and hinge, and should be installed by someone that has the necessary tools. However, pre-hung and primed doors can be installed with a minimum of effort, and the installation can be accomplished in a matter of hours.
Begin by pulling the hinge pins and removing the old door from the opening. If the hinge pins are rusted, drive a pointed awl or framing nail into the hole at the bottom of the hinge to free the pin. Remove the old hinges from the jamb and bring one along for comparison when purchasing the new butts.
If a pre-hung door has been selected, the jamb and casing trim must be replaced. To remove the jamb, use a reciprocating saw with a metal cutting blade to cut the nails that are holding it in place. Work the blade into the seams along each side of the jamb, then across the top to free the jamb.
To install a pre-hung door, begin by removing the hinge pins, and separate the new door from the jamb. Plumb one side of the opening and attach the jamb tight to this side, using wood screws or #8 finish nails. Shim the opposite side of the jamb and attach it in the same manner. Re-hang the door in the jamb and replace any casing trim. Install the lock and the strike plate to complete the installation.
For a mortised door, install the hinges on the door, and split the top hinge by pulling the hinge pin. Measure from the top of the door to the top of the upper hinge, deduct 1/8″ and use this measurement to locate the top of the upper hinge on the jamb. Mortise for the upper hinge and hang the door on this single hinge. Transfer marks for the remaining hinges to the jamb, and mortise for these. Re-hang the door, attach the hinges and install the lock.