How to Upgrade Interior Doors – Affordable DIY Door Makeover

Have you ever looked at your doors and thought, “These belong in a time capsule, not my house”? Same. I had 1970s hollow core doors throughout my entire home, and I finally did something about it. This DIY door upgrade uses trim, paint, and a new doorknob to completely transform tired old doors – no door replacement required. If you want to upgrade interior doors on a budget, you’re going to love how simple (and satisfying) this is.

If you’re tackling a bigger space refresh at the same time, check out how I turned my dysfunctional coat closet into something actually beautiful – the door makeover and the closet overhaul happened in the same project.

Supply and Product Links for This Interior Door Upgrade

Lumber

• Trim – Available at Lowe’s; used to create the decorative framed panels on the door

Tools

• Trim Puller – For prying off mirrors or existing trim without wrecking the door
• Brad Nailer – Nails lightweight trim to the door without splitting it
• Tape Measure – For marking trim placement on the door
• Miter Shears – Cuts trim at 45-degree angles for clean mitered corners
• Milwaukee Drill Combo Set – For removing and installing the doorknob and latch mechanism
• Small Level – Ensures trim pieces are straight before fully nailing
• Small Paintbrush – For cutting in around hinges, trim edges, and the door frame
• Mini Paint Roller – Applies primer and paint to the flat door surface with a smooth finish
• Caulking Gun – For applying caulk neatly along the trim seams

Supplies

• Brad Nails 5/8″ – Short nails sized right for lightweight trim on hollow core doors
• Painters Tape – Masks hinges before spray painting and supports mirrors during removal
• Black Rust-Oleum Satin Paint and Primer in One – Used to spray paint hinges from gold to black
• BIN Ultimate White Primer / Stain Blocker – Primes the door and frame before painting
• Caulk – Seals the seams between trim and door for a seamless built-in look
• Dap DryDex Spackling – Fills brad nail holes with no sanding required; lazy DIYer approved
• Wood Filler – More durable alternative to spackling for nail holes; requires drying and sanding
• Bondo – Two-part filler for a permanent, hard finish on higher-quality doors
• Door Knob – Fresh hardware makes a huge difference in the final look
• Paint: Accessible Beige by Sherwin Williams – warm neutral that works beautifully with black hardware

Step 1: Prep Your Old Interior Door for the Upgrade

Before anything else, you need a clean, smooth door surface to work with. Here’s how to prep depending on what you’re starting with.

If you’re starting with a normal door:

This part is easy. Remove the doorknob and latch mechanism, then wipe down both sides of the door with a damp cloth to remove any dust or grease. If the surface feels rough or has any texture, give it a light pass with 150-grit sandpaper on your Handheld Electric Sander, then wipe it down again. That’s it -you’re ready to prime.

If your door has a mirror on it (like mine did):

Here’s where it gets fun. My closet door had a full mirror glued to the inside, which had to go. One attempt with the trim puller made it clear this wasn’t going to be graceful. Here’s what worked:

1. Tape the mirror heavily with painters tape in multiple directions so if it breaks, the tape catches the pieces.
2. Tap the trim puller slowly and carefully behind the mirror using a hammer to separate it from the door. (Mine had 5 adhesive squares per section – fun surprise.)
3. Sand off the adhesive residue with a handheld electric sander with fresh 150-grit sandpaper. I tried sanding by hand and lemon essential oil first. The sander won.
4. Wipe down both sides of the door with a damp cloth to remove sanding dust.
5. Remove the doorknob and latch mechanism.

⚠️ Important: Tape the mirror generously before prying. Even with tape, mine still broke a little. Better safe than a pile of mirror shards.

Step 2: Spray Paint the Hinges to Upgrade Interior Doors on a Budget

This step alone makes such a difference. All my hinges were builder-grade gold – and I painted them black in minutes. Seriously, this might be the easiest upgrade interior doors trick that exists.

1. Use painters tape to mask off the door around each hinge.
2. Hold a small piece of cardboard behind the hinge as a paint shield.
3. Spray with black Rust-Oleum Satin Paint and Primer in One. Let dry fully before touching.

That’s it. New hinges in seconds. Chef’s kiss.

Step 3: Prime the Door for the DIY Door Makeover

Once the hinges are dry, it’s time to prime – and if you want to upgrade interior doors that actually look custom and not DIY-ed, don’t skip this step. Primer seals the surface and gives your paint something to grip

1. Use a small paintbrush for the hinge areas and frame creases.
2. Use a mini paint roller for the flat door surface – it covers faster and leaves a smoother finish.
3. Back-roll over any brush marks with the roller. Since this is just primer, it doesn’t have to be perfect.
4. Let dry completely before moving to trim placement.

Step 4: Measure and Mark the Trim Placement for Your DIY Door Upgrade

With the primer dry, it’s time to figure out where your trim boxes go. There’s no wrong answer here – the beauty of this method is that you can upgrade interior doors of any size or proportion and it’ll look intentional either way. Here’s exactly how I mapped mine:

For the upper frame:

1. Measure 5 inches down from the top of the door and mark the center.
2. Measure 5 inches in from the left side and mark.
3. Measure 5 inches in from the right side and mark.
4. From the top center mark, measure 36.25 inches down and mark – that’s the bottom of the upper frame.

For the lower frame:

1. Measure 5 inches down from the bottom of the upper frame mark – that’s where the lower frame starts (I also tried to center it around the doorknob).
2. Use the same 5-inch side margins as the upper frame.
3. Measure 5 inches up from the bottom of the door and mark center.
4. From your 5-inch side marks, measure across – the top and bottom trim pieces for both frames should be 14 inches.
5. The lower frame side pieces measured 26.25 inches.

Your exact measurements will vary based on door height – just keep the proportions consistent and you’ll be fine. I have a skinnier door in one of my hallways and you can see below in the picture how narrow I made the trim.

Step 5: Cut and Nail the Trim for the DIY Door Upgrade

With your measurements in hand, it’s time to cut the trim (mine came from Lowe’s) and nail it to the door. I used miter shears set to a 45-degree angle.

Cutting the trim:

1. Cut one angled end on your trim piece.
2. Measure to your needed length (e.g., 36.25 inches for the upper side pieces) and cut the opposite end at a 45-degree angle in the opposite direction — this creates the mitered corners. Flip the shear angle before cutting.
3. Repeat for all pieces: 2 side pieces at 36.25 inches, 2 side pieces at 26.25 inches, and 4 top/bottom pieces at 14 inches.

Nailing the trim:

1. Place the first piece (top of the upper frame) and secure with one brad nail in the center using your brad nailer.
2. Check with a small level before adding more nails.
3. Add the remaining three pieces of the frame, each with one brad nail, lining up corners as you go.
4. Once all four pieces are tacked and corners are aligned and level, go back and add more 5/8″ brad nails to secure everything.
5. Repeat for the lower frame.

⚠️ Important: Don’t fully nail each piece before building out the whole frame – if a corner doesn’t meet right, you want to be able to adjust. I made that mistake in the image below. Tack everything first, then confirm level and square before finishing.

Since these are lightweight trim pieces on a hollow core door, brad nails alone are plenty. If you’re worried, a little construction adhesive on the back of the trim doesn’t hurt.

Step 6: Caulk the Trim Seams on Your Interior Door Makeover

With the trim nailed up, caulk the seams between the trim and the door. This is honestly what separates a DIY interior door upgrade that looks homemade from one that looks like it came that way – don’t rush it

1. Cut the tip of the caulk tube at a small angle – this controls flow and keeps it neat.
2. Load into a caulking gun and run a thin bead along each seam.
3. Smooth with a baby wipe, then a clean finger, then another baby wipe to clean up excess.

This step is genuinely easy enough to hand off to a kid. I’m not kidding. Hand them a baby wipe and let them feel helpful.

Step 7: Fill Nail Holes and Paint Your Upgraded Interior Door

Almost there. Fill the brad nail holes, then paint.

Filling nail holes:

• For a quick, easy fix: Dap DryDex Spackling. Press it into nail holes, wipe clean with a damp sponge while still wet, no sanding needed. It doesn’t shrink in tiny holes the way caulk does.
• For a sturdier fix: wood filler. Let it dry, then sand smooth.
• For a permanent fix on higher-quality doors: Bondo is a two-part system that dries rock hard and sands beautifully. It’s more work, it smells, and you’ll need to sand and deal with dust – but it hides imperfections like nothing else.

I went with spackling. These are 1970s hollow core doors that I plan to replace eventually – they’re getting the budget treatment, and I stand by that decision.

Painting:

Once holes are filled and smooth, paint the door with your chosen wall color. I used Accessible Beige by Sherwin Williams. Apply with the mini paint roller for the flat door surface and the small paintbrush for the trim edges and frame.

Then install a fresh doorknob and latch mechanism and you’re done.

This DIY door upgrade transformed a flat, dated hollow core door into something that looks intentional and custom – for the price of some trim and a can of paint. I’ve done this same process on my hallway doors too, and every single one looks a thousand times better.

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More DIY Door and Home Upgrade Projects

Ready to keep going? Here are a few more projects you’ll love:

• Beautiful Coat Closet Makeover – The full overhaul that went along with this door upgrade. Functional and cute? Yes, both.
• How to Paint a Front Door in 3 Easy Steps – Take the curb appeal up a notch with this simple front door painting tutorial that’ll have your entryway looking brand new in a weekend.
• Weatherstripping a Front Door to Save on Energy Bills – While you’re upgrading your doors, don’t skip this easy fix that keeps drafts out and your energy bills down.

FAQs About How to Upgrade Interior Doors