Few home improvement jobs require more precision than installing interior doors. A door has to hang exactly right in order to close correctly and not appear crooked. The process can take several hours and requires at least a moderate degree of ability to get it right the first time. Hanging a door correctly is considered one of the true measures of carpentry skill. Installing interior doors can be made slightly easier through the use of pre-hung doors, although there is extra monetary cost associated with their use.
Before installing a door, it is essential to check the opening to make sure that all corners are square and that the floor is level. If the framing around the door is not square to within very narrow tolerances, the installation can be protracted and highly frustrating. Wherever they are needed, corrections can be made by sliding shims into place until the edge is level or plumb. This one step takes a large amount of the hassle out of installing interior doors.
If a pre-hung door is being used, it can be set into place and then shimmed to ensure accurate angles. To set the door in place, the bottom should be set down in place, and the top then moved into the frame. It may be wise to have help on the other side of the door to receive it and help shift the door, if needed. Once the frame around the door has been shimmed, finishing nails should be nailed through both the door jamb and the shims, into the surrounding frame.
Although a pre-hung door comes with the door already attached to the hinges and jambs, it can be advantageous to remove the door and hinges while installing the jambs to the door frame. This will allow for more exact adjustments without the awkwardness of having to also hold the weight of the door all the while. Whether this is done or not is up to the person installing the door. But, as a general guideline, if the person performing the installation does not have a comfortable level of experience in doing so, he may want to leave the door and hinges attached. This eliminates the step of reattaching the hinges and therefore rules out the possibility of making a mistake in that step.
Mounting the hardware is the last step to installing interior doors. This is a simple procedure, requiring no more expertise than that needed to use a screwdriver. The only complication that may arise is if the strike plate is too large for the indentation that has been made in the jamb. In this case, the indentation, called a mortise, will need to be chiseled out to accommodate the strike plate.