How to Replace an Exterior Door Without Replacing the Frame

Replacing an exterior door without changing the existing frame is a cost-effective way to improve your home’s curb appeal, security, and energy efficiency—without the hassle and expense of a full-frame replacement.

If your door frame is still solid and square, you can install a slab door (just the door itself, without the frame) and save time, effort, and money.

In this guide, we’ll walk you through everything you need to know, from checking compatibility to the installation process, including tips and common mistakes to avoid.

Tools and Materials You’ll Need

Before starting, gather the following:

Tools:

Measuring tape
Chisel
Hammer or mallet
Screwdriver or drill
Utility knife
Wood shims
Level
Sandpaper
Square
Sawhorses or a workbench

Materials:

New slab door
Exterior-rated hinges
Exterior-rated screws
Wood filler or caulk
Weatherstripping (optional)
Exterior paint or sealer (if the door is unfinished)

Step 1: Confirm That the Frame Is in Good Condition

Before purchasing a new door slab, inspect the existing frame:

Check for water damage, warping, or rot
Confirm the frame is square by measuring diagonally from corner to corner—both measurements should match
Ensure the threshold is sturdy and not cracked

If the frame is damaged or misaligned, a full prehung door replacement is likely necessary.

2. Taking precise measurements

Accurate measurements ensure your new door fits the existing frame perfectly.

Measure:

Height: Top to bottom
Width: Side to side
Thickness: Most exterior doors are 1 ¾ inches thick
Hinge locations: Measure from the top of the door to the top of each hinge
Doorknob & lock height: From the bottom of the door to the center of the knob/lock

Write all measurements down and take them with you when shopping for a replacement slab.

Some hardware stores can custom-cut and bore holes in the slab based on your measurements.

Step 3: Choose the Right Replacement Door

When selecting a slab door:

Choose exterior-grade materials like steel, fiberglass, or solid wood
Ensure the door can be cut or modified if needed
Match the swing direction (inswing vs. outswing, left vs. right)

You can also opt for a blank slab door if you’re comfortable cutting hinge mortises and boring holes yourself.

Tip: Fiberglass and steel doors offer better weather resistance than wood.

Step 4: Remove the Old Door

Open the existing door fully
Unscrew the hinge pins using a screwdriver and mallet (start from the bottom)
Carefully lift the door off the hinges and set it aside
Save the hinges if they’re in good shape and compatible

Step 5: Transfer Hinge and Lock Measurements

Place the old door on top of the new door slab, aligning the tops.

Mark the hinge locations on the new door
Trace around the hinge plates for mortising
Mark the doorknob and deadbolt positions if pre-bored holes are not included

Accuracy is key. Use a square to ensure all marks are level and straight.

Step 6: Cut Hinge Mortises (If Needed)

Use a utility knife to score the hinge outline
Chisel out the wood inside the marked area until it’s the depth of the hinge plate
Test fit the hinge and adjust as necessary

Pre-mortised doors make this step much easier—ask your supplier about customization services.

Step 7: Install Hinges

Screw hinges into the mortised areas using exterior-rated screws
Test the door by placing it in the frame to ensure the hinges align with the frame-side counterparts

Use shims under the door during test fitting to simulate proper clearance and positioning.

Step 8: Fit the Door Into the Frame

With help or using shims:

Position the door in the frame
Insert hinge pins
Open and close the door to check for rubbing or gaps

Adjustments:

Plane or sand the edges if the door is too tight
Add shims behind hinges to adjust alignment
Sand the bottom slightly if the door drags on the threshold

Tip: Leave a 1/8-inch gap around the edges for expansion and clearance.

Step 9: Install Lockset and Hardware

If your new door isn’t pre-bored:

Use a hole saw and spade bit to cut the doorknob and deadbolt holes
Install the knob, deadbolt, strike plates, and latch

Ensure that:

The latch aligns with the strike plate
The deadbolt locks smoothly
The weather seal isn’t compromised

Step 10: Seal or Paint the Door

If your door is unfinished or you’ve planned/sanded it:

Apply a primer (if painting)
Use exterior-grade paint or polyurethane sealer
Don’t forget to seal the top and bottom edges

Unsealed edges can absorb moisture, leading to warping or rot.

Optional: Add or Replace Weatherstripping

Check the weatherstripping around the door frame. If it’s worn or missing:

Replace it with new foam, rubber, or vinyl stripping
Install a new door sweep to block drafts at the bottom

This improves energy efficiency and keeps moisture and pests out.

Common Mistakes to Avoid

Skipping measurements: Always measure everything twice before cutting or buying
Failing to seal the door, Especially the top and bottom edges
Using interior hardware: Only use exterior-grade hinges and screws
Misaligning hinges: Even minor errors can cause improper swinging
Forgetting shims: These are essential for even fitting and leveling

Final Thoughts

Replacing an exterior door without changing the frame is achievable for a skilled DIYer. Precision in measuring, cutting, and fitting is crucial. With the right tools and a patient approach, you can save hundreds of dollars and still achieve a durable, secure, and attractive result.

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