Installing a pre-hung door is much simpler than purchasing the raw materials and building a door from scratch. Pre-hung doors come already fastened to the door frame, and you can order them to size. Pre-hung doors also eliminate the time-consuming process of routing a space for the door hinge and doorknob hardware (like the faceplates), and the holes are already cut for the latch and doorknob. With a pre-hung door, you can install a typical interior door in about 15 minutes, and this article will provide pictures and text to walk you through each step.

Pro-Follow Update: If you keep up with our Pro-Follows, you’ll recognize these pictures are from the basement remodel with contractor Joe Bianco. As you can see, the painters have been through, and now it’s time to install doors and baseboard. If you’d like to read about the work that has already taken place, here’s what we’ve covered so far:

• Day 1: Framing
• Day 2: Rough-in plumbing
• Day 3: Rough-in electric
• Day 4: Hanging and finishing drywall

Become and email or RSS subscriber to stay current on the basement remodel and all of our Pro-Follow series. Later this week, I’ll be sharing another Pro-Follow for installing wainscoting in a kitchen.

Door Sizing and Specifications

It’s important you have all the necessary information before you purchase a pre-hung door. Here are the dimensions and information you’ll need.

Width
During Day 1, the framers built door openings, and the size of the door was written as “feet/inches.” For example, a 4/0 door (read: “four zero”) indicates a 4′, 0″ door, and a 2/6 door indicates a 2′, 6″ door. In addition, the framers further extend the opening by 2″ (1″ on each side) for hanging and shimming the door. So a 4/0 door opening will actually measure 48″+2″ = 50″ across.

Pro-Tip: Door trim increases the overall width, and a 4/0 pre-hung door will measure about 55″ across after installation.

Height
Door height follows the same nomenclature as door width. All the doors in this basement are 6/8 (80″) tall which is a standard height. The framers add 2-1/2″ to the height so a 6/8 door will actually sit in an 82-1/2″ opening, and this allows the door to clear the flooring.

Jamb Width
The jamb width is the same as the wall thickness, and this basement, like many other interiors, features 2×4 framing with 1/2″ drywall. To calculate the typical door jamb width, add 3-1/2″ (actual width of a 2×4) + 1/2″ + 1/2″ = 4-1/2″. Exceptions to this include doorways to unfinished spaces like the HVAC closet which only have drywall on one side.

Right or Left-Handed Doors
Doors are either right-handed or left-handed, and this needs to be specified when you purchase.

Pro-Tip: The easiest way to determine door-handedness is to place your backside to the door hinge. If the door opens left, it’s a left-handed door and vice-versa.

Tools & Materials

Here are the tools you’ll need:

• Hammer
• Pliers
• 4′ Level
• Finish nailer (with compressor)
  * finish nails can be driven by hammer and nail-set with pre-drilled holes

These are the materials you’ll need:

• Shims
• 1/2″ spacers (drywall works well)

Step 1: Place Spacers

Joe and his crew had some 1/2″ drywall left over, and they used pieces to act as spacers. They placed a small square on the left and right side to keep the door off the concrete.

Step 2: Remove Nails, Staples, Braces

Pre-hung doors come with double-headed nails to hold the door in place. Depending on the door style (single, double-door, etc.) you may have nails in both sides and the top.

Braces and staples keep the inside and outside door trim in place, and sometimes the staples are embedded in the wood. Thoroughly examine the door and remove all staples and braces.

Step 3: Separate Inside and Outside Trim

The inside and outside trim will separate with some gentle “encouragement.” At this point, the frame will not support much weight so work carefully.

Pro-tip: If you’re installing a double-door, there will be a bottom brace securing the underside of the doors. Leave this brace until after nailing the trim (Step 6).

Step 4: Move Door in Place

Slide the door in place on top of the spacers and snug against the walls.

Step 5: Level Hinge Side

Use a 4′ level to plumb the hinge side of the door. Make this as exact as possible otherwise the door will be unbalanced.

Step 6: Finish Nail Face of Trim

Finish nail the face of the trim every 18″ or so. Before nailing the knob-side trim, double-check the door reveal. If the factory built the door square, you shouldn’t have to make adjustments.

Step 7: Insert Shims

There will be a space between the door jamb and the door framing. Insert two shim (pointed in opposite directions) to tightly fill that gap. Place three pairs of shims, evenly spaced on both sides of the door. Be sure that one pair of shims sits behind the top-most hinge.

Editors note: You may see alternate instructions that indicate shims should be placed before the door. While a valid option, the method described here is faster. Since the door is already level, all you need to do is fill a gap (rather than check for plumb, adjust shims, then recheck).

Step 8: Add Second Trim and Nail

Fit the second piece of trim tight against the wall on the opposite side of the doorway. Nail the face of the trim just like before, then nail into the door jamb and through the shims.

Pro-Tip: Over time doors can shift position. To keep the door in place and balanced, temporarily remove the top-most hinge. Next, pre-drill a hole and drive a 3″ screw through the jamb and shims and into the framing.

Finished