how to extreme

Replace an Interior Door

Doors, Windows & Doors November 12, 2012 Sonia


No matter how much you enjoy doing home repairs and improvements, you probably have other things you’d rather do. That’s why when faced with most tasks, I’m looking for how I can do a quality job in the most cost-effective and efficient manner possible.

When an interior door needs to be replaced, often a good option is to replace just the door blank rather than removing the casing and door jamb. Obviously the door jamb and trim must be in good condition to do this, but the right approach can save time and money. It also eliminates the need to find trim that matches the rest of the house.


To purchase the right door for the opening you’ll need to get some measurements. If the existing door is still in place and it fits right, you can measure it and match it. If there is no door in the opening, measure vertically from the floor to the underside of the jamb header, and horizontally between the jamb sides in front of the door stops. These measurements are usually referred to in feet and inches with the horizontal listed before the vertical. In the case of our door replacement we needed a door 2 feet by 6 feet, 8 inches. (Note: Door and window sizes are often written with the feet as an integer and the inches as an exponent.  So a door that measures 2 feet 4 inches in width and 6 feet 8 inches high will be written 2468.)

Unless you are very familiar with door types and wood species, a digital photo is a good way to match your door type. Before leaving the house, shoot the overall door and get a close-up shot of the wood grain as well. Take your camera with you to the home improvement store to find the door you’re looking for.

Because you are using the existing door jamb with its hinge and strike locations already determined, it’s best to get a door with no hardware holes or hinge mortising. These will all need to be matched to the door jamb on site.

Here’s how to get that door installed and opening with ease:

Step 1: Put the door in the opening and adjust it with shims until you have even reveals (spaces) between door jamb and door blank. A shim at the floor can be about 1/4-inch thick on hard surfaces. On carpeted areas the door should just clear the top of the carpet nap.

Step 2: Put a mark on the door at the top and the bottom of the strike-plate mortise, which is located on the door jamb. Find the center between the two marks. This will be the center of the door latch.

Step 3: Measure from the bottom of the door to the latch center mark, and transfer this mark over to the center of the back latch set (about 2-3/8 inches from the door edge).

Step 4: Put a cross mark at 2-3/8 inches from where the edge of the door will be after it is trimmed.

Step 5: Mark where the door needs to be trimmed. If the jamb sides are fairly parallel but the top is not even all the way across, you may need to trim at an angle to follow the jamb.

Step 6: Remove the door from the opening and mark the top of the door indicating which surface is the outside, inside, hinge side and strike side.

Step 7: Place the door blank on sawhorses. Using a hole saw, drill a 2-1/8-inch hole through the door where the door latch set will be installed. The centering bit should start at the cross mark you made earlier. Drill until the centering bit goes through the door, turn the door over and finish cutting from the other side.