Flat Panel Door Makeover | Upgrade Ugly Hollow Core Doors

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DIY Flat Panel Door Makeover

MATERIALS:

• Trim (I used 11/16 in. Thick x 1-3/8 in. Tall x 8 ft. Length White Base Cap)
• Primer (I used Zinsser 1-2-3 Primer)
• Paint (I used Behr Ultra White Extra Durable Satin)
• 220 grit sandpaper (if removing varnish, 60 or 80 grit as well)
• Varnish remover (optional)
• Liquid nails
• 1” brad nails
• Spackling paste
• Caulk 
• Wood filler

TOOLS:

• Miter saw
• Orbital sander
• Cordless brad nailer
• Caulking gun
• Spray paint gun
• Tape measure
• safety glasses
• face mask (for dust)
• ear protection

Step 1: Prep Work is Key

Before you get started with the fun stuff (like paint!), it’s essential to prep the doors properly. This involves removing the existing finish and patching any holes or imperfections.

Start by removing the existing finish from your doors. This will allow the paint to adhere. Depending on the stubbornness of the finish, you can use sandpaper or a varnish remover.

TIP: Ensure you work in a well-ventilated area and wear a mask when using varnish remover.

Also, it is important to patch any holes or imperfections in the door with a filler.

Then, sand the door with 220 grit sandpaper to give you a smooth finish. 

Step 2: Measure your door

After prepping the doors, it’s time to add the trim.

But before you can start cutting with your saw, you must determine your cuts by taking measurements. Here are the pieces you need for one side of a door:

• (4) top and bottom trim pieces
• (2) top side pieces (above the door knob)
• (2) bottom side pieces (below the door knob)

Here’s a handy trick to getting the measurements right.

Top and bottom trim pieces:

1. Measure the width of your door.
2. Subtract 10 inches (5 inches from each side) to account for the trim.
3. This will give you the length for the top and bottom pieces of trim. You need four (4) trim pieces per side for the door you measured. 

Top side pieces (above the door knob):

1. Measure the door knob faceplate (it’s the metal plate on the side where your door latches closed). 
2. Subtract this measurement from 6”. For example, my faceplates are 2-1/4”, so my measurement after is (2.25” – 6”) 3.75”.
3. Divide this measurement in half and add 5 inches to this new measurement; this will give you the amount to subtract to space the trim 5 inches away from the sides. Example: 1.875” + 5” = 6.875″ or 6-7/8″
4. Measure the length of the door from the top to the top of the knobs faceplate. 
5. Subtract the last determined amount from this number. Example: 39-5/8” (39.625) – 6.875” = 32.75” or 32-3/4″
6. This will give you the length for the top-side trim pieces. You need two (2) trim pieces per side of the door. 

Bottom side pieces (below the door knob):

1. Take the measurement you determined in the top side pieces. Example: 6.875” 
2. Measure the length of the door from the bottom to the bottom of the knobs faceplate. 
3. Subtract the determined amount from this number. Example: 35-1/2” – 6.875” = 28.625” or 28-5/8″
4. This will give you the length of the trim on the bottom side. You need two (2) trim pieces per side of the door. 

Step 3: Cutting and assembling the trim

Once you have your measurements, it’s time to cut the trim pieces. For a nice, finished look, cut them at 45-degree angles.

After cutting the trim, you will install the trim to the door. 

Place the door on a flat surface and mark all its sides 5” away from the edge. 

Each door will have two trim boxes. Starting with the bottom panel, apply liquid nails to the back of the bottom trim. Place that trim piece 5” away from the bottom edges of the door (you just marked this), and the 45-degree cuts are facing inward to the door. 

Then, nail the trim to the door using 1” nails. 

Now, install one of the bottom side trim pieces the same way.

Next, you want to install the last side trim piece and top trim piece at the same time to ensure that your corners meet. 

Do this by applying liquid nails to the bottom of both trim pieces. 

Then, place the trim pieces on the door so that they create a box with the other trim pieces already installed. 

Once all the corners are flush, nail each trim piece into place. 

Continue this process again for the top trim box. 

Then flip the door around and install the boxes on the other side, as well as any other door needing trim. 

Step 4: Sand, Fill, Caulk, and Paint

With the trim in place, it’s time to prep for painting. Here’s what you need to do:

• Sand down any rough edges or imperfections.
• Make sure the nails are slightly indented into the wood.
• Fill in any nail holes with spackling paste.
• Caulk all the seams between the trim and the door.
• Apply primer and paint your doors.

TIP: For a flawless finish, consider using a spray paint gun.

I painted all my doors at the same time using a spray painter. I raised them off the ground by placing them on 2x4s and then nailing the tops with scrap board like an accordion.

BONUS STEP: Paint door knobs

Because we have old door knobs that are not a standard size (the hole in the door), I decided to repaint my door knobs.

I painted my doorknobs years ago, and they held up really well. I followed my own OLD tutorial on painting door knobs.

Step 5: Reinstall and Admine Your Upgraded Doors!

Once the paint is dry, carefully reinstall your doors and step back to admire your handiwork! You’ve transformed those boring old doors into something beautiful, all on your own.

FULL PROJECT VIDEO:

Are you better with visuals? Check out the full project video below, and don’t forget to subscribe on YouTube so you don’t miss out on future projects!

https://youtu.be/KI26xnnD0Oc

This flat panel door makeover is a cost-effective way to upgrade the look of your home. So ditch the boring doors and embrace the power of DIY!