Installing Interior Doors


There are two door options when you're working with interior entry doors. One is a pre-hung door assembly that comes complete with hinges and a doorjamb. The other is what's often referred to as a slab door, or just the door by itself. Installing either type of these interior doors will be easier once you understand the basics.

Basics of Putting in a New Door

On the surface, it may look like a good deal to purchase a replacement slab door and install it in an existing doorway, but this is usually a bad idea. Putting in a new door successfully involves a number of factors that don't have much to do with the door itself. The opening the door's going into has to be plumb, parallel and square in order for the new door to fit well. Just because it's replacing another door with the same overall dimensions, material and appearance isn't a guarantee of success, either.

Evaluating Slab Door Installations

Houses settle as they age, and entryways and doors settle too. An existing door and jamb combination will often distort to accommodate one another in your home, so the fact that the old door didn't bind or drift open on its own doesn't mean that your entry will accommodate a new slab door without problems.

Before you make a decision about which type of new door installation you want to make, check these elements of your existing door opening:

  • Make sure the door swings freely.
  • Check the door header to verify that it's level.
  • Inspect the top corners of the opening to see if they're square.
  • To insure that the door will fit in the frame, check the old setup for gaps and mismatches.
  • Use a level to check at intervals along the length of the jamb to verify that the opening is consistent throughout.
  • Don't forget to take a look at the walls on either side of the door to make sure they're plumb.

If everything looks okay, you may be able to install a replacement slab door. Unfortunately, it's a rare installation that's straight and true enough to accommodate a slab door without additional work. Although it may seem counter intuitive, it's often easier to replace the door and the jamb with a pre-hung door than it is to try and fit a slab into an existing frame.

Tips for Installing Pre-Hung Doors

The nice thing about pre-hung doors is that a lot of the fussy work has already been done for you. Although you have to work with the rough opening of the doorway, if you measure carefully, the installation is usually pretty straightforward. These tips will help:

  • Before you buy a door, measure the thickness of the wall. Wall thickness isn't standard and will vary based on the types of materials used.
  • Doors should swing into rooms and away from closets, so the application does matter.
  • Check the rough opening by measuring it at lease a couple of times. It should be one inch taller than the finished door and two inches wider. The extra will give you wiggle room to make adjustments in openings that are less than perfectly square.
  • Pre-hung doors may not come with knobs and locks included, so check the promotional information carefully to make sure you know what's included and what's not.
  • If you're installing a door over carpet or tile, measure carefully to allow for the elevation of the flooring material before you hang the door.

Installing an Interior Door Is Easier Than It Seems

Armed with the right information, a level, shims and a pry bar, installing interior doors can be easier than you think. Once you have all the tools and materials in place, you should be able to get the job completed in two hours or less.

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Installing Interior Doors