Feature Story

"Add Trim to Built-in Bookcase: Step-by-Step Guide"

By Carol Jun 28, 2026

Adding trim to a built-in bookcase can significantly enhance its aesthetic appeal and provide a polished, finished look. This guide will walk you through the process, from choosing the right trim to applying it like a professional. Let's dive in!

Choosing the Right Trim for Your Bookcase

Adding Trim To Cabinets & Bookshelves
Adding Trim To Cabinets & Bookshelves

The trim you choose should complement the style of your bookcase and the overall decor of your room. Here are a few options to consider:

Adding Moulding to Ikea Billy Bookcase
Adding Moulding to Ikea Billy Bookcase
  • Wood Trim: This is a classic choice that can be stained to match or contrast with your bookcase. It's great for adding a touch of warmth and elegance.
  • MDF Trim: Medium-density fiberboard is a versatile and affordable option. It can be painted or stained and is easy to cut and install.
  • PVC Trim: This is a durable, low-maintenance option that's perfect for humid environments like bathrooms or laundry rooms. It's also a good choice if you're on a budget.

Materials and Tools You'll Need

an ikea billy hack is shown with the instructions for how to build a bookcase
an ikea billy hack is shown with the instructions for how to build a bookcase

Before you start, make sure you have the following materials and tools on hand:

  • Trim
  • Miter saw or miter box
  • Jigsaw or circular saw
  • Nail gun or finish hammer and nails
  • Wood glue
  • Sandpaper (120-grit and 220-grit)
  • Stain or paint (optional)
  • Tape measure
  • Pencil
  • Safety glasses
Shop My Library Trim - Palmetto Highway
Shop My Library Trim - Palmetto Highway

Measuring and Cutting the Trim

Accurate measurements are crucial for a professional-looking result. Here's how to measure and cut your trim:

  1. Measure the length of each side of your bookcase, including the top and bottom.
  2. Transfer these measurements to your trim, marking them with a pencil.
  3. Use a miter saw or miter box to cut 45-degree angles at each corner. This will create a seamless, mitered corner.
DIY Office Built-Ins: IKEA Billy Bookcase Hack
DIY Office Built-Ins: IKEA Billy Bookcase Hack

Attaching the Trim to Your Bookcase

Now that you have your trim cut, it's time to attach it to your bookcase. Here's how:

  1. Apply wood glue along the edge of your bookcase where the trim will be attached.
  2. Position the trim in place and use a nail gun or finish hammer and nails to attach it. Space your nails about 6-8 inches apart.
  3. Use a clamp to hold the trim in place while the glue dries, if necessary.
How to Convert Bookcases into Built-Ins
How to Convert Bookcases into Built-Ins

Finishing Touches

Once the glue is dry and the nails are secure, it's time to finish your trim. Here's how:

a person is painting the inside of a white bookcase with paint rollers on it
a person is painting the inside of a white bookcase with paint rollers on it
DIY Bookcase Tutorial (DIY built in, all the details!!)
DIY Bookcase Tutorial (DIY built in, all the details!!)
380K views · 7.5K reactions | DIY Living Room Built Ins with fireplace Part 3 | By Designing | Welcome to part three my living room built ins. If you include the flooring and the fireplace build, this project has taken me just over a year to complete and I cannot wait for it to be done. Last time we left off, I had installed my cabinets and built four separate shelving units out of oak boards and I decided to stain my shelves to try to keep some natural wood on this project. I got the best looking thin plywood that I could find for the back of these shelves. I didn't want super thick plywood because then my shelves would stick out too far. I started attaching all my backs and realized very quickly that I was just building a playground attached. I also primed and painted all of these back pieces before attaching them so I wouldn't have to tape off my stained shelves to paint them later. After going through far more paint samples than I want to admit or that I ever want to see again, I finally decided on a color and went ahead and started priming and painting all of my cabinets. I usually like to prime by hand because primer can really clog up your paint sprayer and let's be honest, I just don't have my life together enough to clean my sprayer fast enough for it to not get clogged. So, I used a brush for the edges and then a foam roller for all the flat pieces to prime the cab and then I use my paint sprayer to spray the actual paint on the fronts and the backs. I attached all my shelves into the studs and the walls and now it was time to add some trim to make up for all of those uneven walls and maybe some mistakes. The one side of these shelves is exposed into the dining room so I decided to add a little bit of his shaker style trim around that side to give it a little bit more character instead of just a plain wall. Since no wall is ever straight, I had to use a level on every single one of these trim pieces to make sure that my trim was actually straight and not lining up against the wall and we'll fix that with the caulk later. Filling nail holes and caulking really isn't that bad but I was sick at the end of this project so this is probably my least favorite part of this entire process. This part and the rest of the painting really only took a couple days but since I was sick, it felt like an eternity. Now, before you come at me for painting this wood, I had to use a different type of wood on the trim pieces than I did for the shelves so if I stained them, they wouldn't match. I added battery-powered picture frame lights to the top of these units and then some gold handles to finish it all off. I am so happy to almost be done with this living room project. And I love how it turned out but I'm so ready to put my furniture back.
380K views · 7.5K reactions | DIY Living Room Built Ins with fireplace Part 3 | By Designing | Welcome to part three my living room built ins. If you include the flooring and the fireplace build, this project has taken me just over a year to complete and I cannot wait for it to be done. Last time we left off, I had installed my cabinets and built four separate shelving units out of oak boards and I decided to stain my shelves to try to keep some natural wood on this project. I got the best looking thin plywood that I could find for the back of these shelves. I didn't want super thick plywood because then my shelves would stick out too far. I started attaching all my backs and realized very quickly that I was just building a playground attached. I also primed and painted all of these back pieces before attaching them so I wouldn't have to tape off my stained shelves to paint them later. After going through far more paint samples than I want to admit or that I ever want to see again, I finally decided on a color and went ahead and started priming and painting all of my cabinets. I usually like to prime by hand because primer can really clog up your paint sprayer and let's be honest, I just don't have my life together enough to clean my sprayer fast enough for it to not get clogged. So, I used a brush for the edges and then a foam roller for all the flat pieces to prime the cab and then I use my paint sprayer to spray the actual paint on the fronts and the backs. I attached all my shelves into the studs and the walls and now it was time to add some trim to make up for all of those uneven walls and maybe some mistakes. The one side of these shelves is exposed into the dining room so I decided to add a little bit of his shaker style trim around that side to give it a little bit more character instead of just a plain wall. Since no wall is ever straight, I had to use a level on every single one of these trim pieces to make sure that my trim was actually straight and not lining up against the wall and we'll fix that with the caulk later. Filling nail holes and caulking really isn't that bad but I was sick at the end of this project so this is probably my least favorite part of this entire process. This part and the rest of the painting really only took a couple days but since I was sick, it felt like an eternity. Now, before you come at me for painting this wood, I had to use a different type of wood on the trim pieces than I did for the shelves so if I stained them, they wouldn't match. I added battery-powered picture frame lights to the top of these units and then some gold handles to finish it all off. I am so happy to almost be done with this living room project. And I love how it turned out but I'm so ready to put my furniture back.
How to Build DIY Bookshelves for Built-Ins | The DIY Playbook
How to Build DIY Bookshelves for Built-Ins | The DIY Playbook
Billy in the Bedroom
Billy in the Bedroom
DIY Ikea Bookcase Makeover (No Powertools) - Hattie Kolp
DIY Ikea Bookcase Makeover (No Powertools) - Hattie Kolp
the shelves are made out of plywood boards
the shelves are made out of plywood boards
How to Build Built In Bookshelves on a Budget :
How to Build Built In Bookshelves on a Budget :
the books are lined up on the shelves
the books are lined up on the shelves
These IKEA Billy Bookshelf Makeovers For Creating The Perfect Wall
These IKEA Billy Bookshelf Makeovers For Creating The Perfect Wall
Our First Built In Bookcase
Our First Built In Bookcase
How to Add Trim to Cabinets - Our Home from Scratch
How to Add Trim to Cabinets - Our Home from Scratch
How to Make a Custom Built-In Bookcase Around the Fireplace
How to Make a Custom Built-In Bookcase Around the Fireplace
how to add cream molding to plain bookshelves
how to add cream molding to plain bookshelves
How to add molding to a bookcase
How to add molding to a bookcase
How to Turn Bookcases Into Built-Ins - Thistlewood Farm
How to Turn Bookcases Into Built-Ins - Thistlewood Farm
425K views · 10K reactions | These bookcases originally cost $37 each. Would you have guessed it?! There are lots of creative ways to upgrade these kinds of shelves but I've picked a few beginner friendly simple wa | Creatiffdiy
425K views · 10K reactions | These bookcases originally cost $37 each. Would you have guessed it?! There are lots of creative ways to upgrade these kinds of shelves but I've picked a few beginner friendly simple wa | Creatiffdiy
CUSTOM BUILT-IN: HOW TO FINISH WITH TRIM AND PAINT
CUSTOM BUILT-IN: HOW TO FINISH WITH TRIM AND PAINT
the corner of an empty room with white trim
the corner of an empty room with white trim
Check This Surprisingly Easy Way to Make a Billy Bookcase Built In
Check This Surprisingly Easy Way to Make a Billy Bookcase Built In
  • Sand: Use 120-grit sandpaper to smooth any rough edges, then follow up with 220-grit for a smooth finish.
  • Stain or Paint: If you're staining your trim, apply a stain that matches or complements your bookcase. If you're painting, choose a color that fits your decor. Allow the stain or paint to dry according to the manufacturer's instructions.
  • Seal: Apply a sealant to protect your trim from scratches and moisture. This will also help maintain the look of your stain or paint.

Congratulations! You've successfully added trim to your built-in bookcase. This simple upgrade can make a big impact on the look of your room. Happy DIYing!