When it comes to installing new doors in your home, prehung interior doors and prehung exterior doors are among the most convenient and efficient options available. Unlike traditional slab doors, prehung doors come fully assembled in a frame, making installation much easier for both DIYers and professionals.

In this comprehensive guide, we’ll explore:

• What prehung doors are

• The differences between prehung interior and exterior doors

• Benefits of choosing prehung doors

• Installation tips

• Common mistakes to avoid

By the end, you’ll have a clear understanding of why prehung doors are a popular choice for homeowners and contractors alike.

What Are Prehung Doors?

A prehung door is a complete door system that includes:

• The door slab (the actual door)

• A pre-attached frame (jamb)

• Hinges already mounted

• A door stop (the trim that prevents the door from swinging too far)

• Often includes a pre-cut hole for the doorknob

Unlike a slab door (which is just the door itself without any hardware or frame), a prehung door is ready to install into a rough opening in your wall.

Prehung Interior Doors vs. Prehung Exterior Doors

While both types are pre-assembled, there are key differences:

Prehung interior doors are designed for rooms inside the home (bedrooms, bathrooms, closets), while prehung exterior doors are built to withstand outdoor elements and provide security.

Benefits of Prehung Doors

1. Faster & Easier Installation

Since the door is already mounted in its frame with hinges attached, installation is much quicker than fitting a slab door into an existing frame.

2. Perfect Alignment

Prehung doors ensure that the hinges, frame, and door are perfectly aligned, reducing the risk of misalignment that can cause sticking or gaps.

3. No Need for Mortising Hinges

With slab doors, you must chisel out hinge slots (mortising), which can be tricky. Prehung doors eliminate this step.

4. Better Insulation & Soundproofing (Exterior Doors)

Exterior prehung doors often come with weatherstripping and tight seals, improving energy efficiency.

5. Professional Finish

Since the frame is pre-assembled, the final look is cleaner and more polished compared to retrofitting a slab door.

How to Install a Prehung Door

Installing a prehung door is a manageable DIY project if you follow the right steps.

Tools You’ll Need:

• Level

• Shims

• Hammer & nails (or screwdriver & screws)

• Drill

• Tape measure

• Utility knife

Step-by-Step Installation:

1. Prepare the Rough Opening

• Measure the rough opening to ensure it matches the prehung door size (usually 2" wider and taller than the door).

• Remove any old door and frame if replacing.

2. Insert the Prehung Door

• Place the prehung door into the opening, ensuring it’s centered.

• Use shims to adjust for level and plumb (vertically straight).

3. Secure the Frame

• Nail or screw through the shims into the wall studs.

• Check that the door swings smoothly without sticking.

4. Insulate & Trim

• Add insulation around the frame if needed.

• Install trim (casing) around the door for a finished look.

5. Attach Hardware

• Install the doorknob, latch, and strike plate if not pre-installed.

Common Mistakes to Avoid

1. Not Checking for Level & Plumb

If the frame isn’t perfectly level, the door may not close properly. Always use a level during installation.

2. Over-Tightening Screws

This can warp the frame. Tighten just enough to hold the door securely.

3. Skipping Shims

Shims are crucial for adjusting the door’s position. Without them, the door may sag over time.

4. Ignoring Expansion Gaps

Wood expands with humidity, so leave a small gap (about 1/8") around the frame.

Conclusion

Prehung doors—whether for interior or exterior use—are a smart choice for hassle-free installation and a professional finish. They save time, ensure proper alignment, and reduce the risk of errors common with slab doors.

If you’re renovating or building a new home, consider prehung interior doors for rooms and prehung exterior doors for entryways. With the right tools and careful installation, you can achieve a perfect fit every time.

Ready to upgrade your doors? Browse prehung options at your local hardware store or consult a professional for the best results!