Custom DIY Master Bedroom Window Seat And Bookcase

Today I'm sharing a custom DIY bedroom window seat with storage underneath and a built-in bookcase that we made for our master bedroom.

We are fortunate to have a large private backyard with mature trees that backs onto a lovely green belt. The master bedroom is located on this side of the house. Since buying our 1960s humble abode I've envisioned this room with a much larger window and a window seat underneath to enjoy the view.

That dream was realized recently when we took the plunge and splurged on a large custom window. What a difference it made and so worth the cost! The next dream to fulfill is building that cozy window seat and flanking the new window with a built-in bookcase, because this gal loves to read.

How to build a window seat with storage underneath and a custom built-in bookcase for a master bedroom..

DIY Bedroom Window Seat

In the before photo below you can see how the original window didn't offer much of a view of our backyard. Nor did it let in much light. I cringe looking at the photo because at the time I was so proud of my gold sponge-painted wall.

The small master bedroom BEFORE a makeover

The photo below is after the new enlarged vinyl-clad window was installed and now the room is filled with natural night.

New enlarged vinyl clad window installed in the master bedroom before building a window seat and bookcase.

The walls have been painted a Benjamin Moore Wedgewood Gray HC-146 color. Plus the sponge-painted feature wall has been replaced with a pretty lattice design. It looks like wallpaper but it's actually stenciled and I share how to do it in my 12 helpful tips on how to stencil a wall tutorial.

In the photo above you can see by the painter's tape around the window that we were in the planning stages of designing the window seat and bookcase. We mapped a template out on the floor with tape as well to ensure a good footprint in this small space.

A custom upholstered cushion on master bedroom window seat.

You may be wondering why we didn't build the window seat flush with the floor and finished with the same baseboard trim as the bookcase and shelving unit flanking it. That certainly would have given the entire unit a seamless custom finish.

But the problem is the only furnace heating duct in the room is situated right under the window. We live in the Canadian prairies and our winters are brutally cold. In order to heat the room, the furnace duct needs unobstructed airflow.

So we chose the simplest route by building it raised off the floor. Then we placed a plastic air deflector on top of the furnace vent underneath the window seat so the airflow is directed into the room.

Alternatively, we could have gone the more labor-intensive and expensive route by closing in the bottom and running furnace ducting underneath with a vent exposed on the front of the window seat.

What You'll Need To Make It

This post contains affiliate links so you can see what products I used or recommended for this project. As an Amazon Associate, I earn a small commission from any qualifying purchases at no extra cost to you. Thank you for your support!

Window Seat Supply List

3/4 x 16 x 72-inch Laminated Pine Project Panels
3/4 x 16 x 36-inch Laminated Pine Project Panels
2" x 3" Lumber
1/8-inch Hardboard
Decorative Pine Trim
Piano Hinge
Locking Lift Up Lid Hinge
3 6-inch Wood Furniture Legs
#8 1 1/2-inch Wood Screws
#8 4-inch Wood Screws
Wood Glue
Baseboard Trim
Serrated Bread Knife (cutting foam)
2-3 inch Upholstery Foam
Zinsser Bullseye 123 Primer
White Satin Behr Paint & Primer For Cabinets And Trim
Foam Roller

Table Saw or Skill Saw With Cutting Guide
Power Drill
Palm Sander
Kreg Shelf Pin Jig

The packages of pre-cut laminated pine project panels pictured below are perfect for building both the window seat and bookcase. They are already cut to the right widths, solid wood, and finished on all sides and we found them at Home Depot.

Pine boards to build a bedroom window seat and bookcase.

See the closet that the laminated panels are leaning against? It used to be an empty void and so we turned the narrow niche into a much-needed second DIY closet with floor-to-ceiling shelving. From the outside, it looks identical to the original master closet but on the inside, it is only 12-inches deep.

Adjacent to the new closet we also made use of the remaining empty void by turning our wall-mount full-length mirror into hidden jewelry storage. I don't know how I lived without it all these years!

Window Seat Dimensions

21" high x 60" wide x 19" deep

Before we get into the nitty-gritty of how the window seat and built-in bookcase were made, I should mention that we are self-taught DIYers and not trained professionals. This step-by-step tutorial is based on our building knowledge only. However, if you are a do-it-yourselfer like us, you'll find these steps helpful if you plan on building one like it too.

DIY Bedroom Window Seat Assembly

The window seat frame is built with 2 x 3 lumber rather than bulkier 2 x 4's. The interior is lined with a smooth 1/8-inch thick hardboard suitable for storing linens and blankets. The exterior of the frame is lined with the laminated pine panels mentioned earlier.

Building a bedroom window seat with storage underneath for linens and blankets..

In the photo above, you can see a cut-out in the hardboard. We didn't bother to move the electrical outlet on the wall because the plug is rarely used. Instead, we made it accessible should we need to use it on rare occasions.

UPDATE - What We Changed

Please note that an electrical outlet inside a cupboard is not to code and we address this further down in the post where we had it moved.

Secondly, we disliked how there was limited storage space in the window seat because of the bulky way in which we built it. We figured out a simpler way to build it and I share those details further down in the post as well.

Window Seat Lid

You'll notice in the photo below that a narrow 3-inch wide pine plate is installed on the back of the window seat. This allows the lid to be fully opened and is used to mount a piano hinge.

Not shown on the inside we installed a locking lift-up lid hinge (see supply list) to hold it up when accessing storage underneath.

Installing a pine hinged lid on bedroom window seat with storage underneath.

The pine lid on the window seat is 14-inches deep to allow for a 2-inch overhang so fingers can easily reach underneath to open the lid.

To soften the blunt edge on both the front and right side of the lid, we used a router with a half-round bit to give it a bullnose profile.

Attaching narrow decorative wood trim on the front of custom bedroom window seat.

In the photo above you can see that we dressed the front of the window seat with narrow-mitered pieces of decorative pine trim. They are attached with wood glue and secured with tape until the glue cures.

Window Seat Installation

The window seat is attached to the wall studs with #8 4-inch wood screws. The front of the bench is supported by three 6-inch wooden legs.

DIY Bedroom Window Seat Shelving Unit

Rather than a long bench that extends the width of the 7-foot window, we decided to build a short shelving unit that matches the bookcase on the opposite side. One can never have enough storage, right?

Shelving Unit Dimensions

21" high x 24" wide x 16" deep

Shelving Unit Supply List

3/4 x 16 x 24-inch Laminated Pine Project Panels
#8 1 1/2-inch Wood Screws
Wood Glue
Baseboard Trim
Small Crown Trim
Zinsser Bullseye 123 Primer
White Satin Behr Paint & Primer For Cabinets And Trim
Foam Roller

Building a small built-in shelving unit on one end of the bedroom window seat.

The small shelving unit is built exactly the same way as the bookcase and you'll find the tutorial for it in the section below.

Installing baseboard trim on the bottom of window seat shelving unit.

It's hard to see in the photo above, but we added a narrow crown moulding along the top of the shelving unit to dress it up. The base is finished with the same baseboard trim as the bookcase.

DIY Built-In Bedroom Bookcase

Now let's move on to how to build the lovely built-in bookcase that flanks the bedroom window seat. We've included the measurements below which can be adapted to whatever size requirement for your space.

Bookcase Dimensions

80" high x 25" wide by 12" deep

Bookcase Lumber Cuts

Sides Panels: 12" wide x 80" long
Top/Bottom Pieces: 12" wide x 23 1/2" long
Five Shelves: 12" x 23 1/2" long

Bookcase Supply List

3/4 x 12 x 96-inch Laminated Pine Project Panels
3-inch Crown Moulding
Baseboard Trim (matching existing baseboards in the room)
Wood Shims
#8 1 1/2 Wood Screws
1 1/2-inch Metal Angle Brackets
Kreg Shelf Pin Jig
Half-Round Router Bit
1/16 Drill Bit (Pilot Holes)
Countersink Drill Bit
Wood Glue
White Latex Caulking
Drywall Anchors

Before assembling the bookcase, this is a good time to drill holes in the side panels to accommodate adjustable shelving.

Drilling Holes For Adjustable Shelving

You can drill holes for the adjustable shelving the hard way by manually mapping out the spaces for each hole or do it the easy way with a handy Kreg Shelf Pin Jig (see supply list) as pictured below.

  1. Cut a small block of wood approximately 10-inches long to use as a guide for starting the first hole.
  2. Clamp the guide at the top edge of the side panel.
  3. Place the jig directly against the guide and use the drill bit provided to drill the holes.
  4. Next, slip the locating pin on the jig into the last hole you drilled.
  5. Repeat this step until you've reached approximately 10-inches near the bottom of the board.
  6. Now repeat the steps above on the opposite top edge of the side panel. The wood guide ensures that the holes are in the exact same position so the shelves sit perfectly level.
  7. Now do the same thing on the other side panel.

To demonstrate the instructions above, I found this shelf pin jig video tutorial that you might find helpful.

Using a handy Kreg Shelf Pin Jig to make holes for adjustable shelves on DIY bedroom built-in bookcase.

This step is completely optional but it gives the bookcase a nice custom look. To soften the sharp edge on the front of the bookcase, use a router and half-round bit to create a bullnose profile along just the front edge of the side panels.

Bookcase Assembly

Assemble the bookcase by attaching the top and bottom pieces to the two side panels as follows.

  1. Ensure the adjustable shelving holes face the inside of the bookcase.
  2. Line up the top piece 3 inches down from the top of the side panels (as pictured below).
  3. With a 1/16 drill bit, make three pilot holes across the top of the side panel.
  4. Use a countersink drill bit in the pilot holes to accommodate the screw head.
  5. Attach the top with wood glue and #8 1 1/2-inch wood screws.
  6. The screws will be hidden with wood filler later.

Alternatively, you could use a pocket hole assembly where the screws are hidden on the inside of the panels using a Kreg Pocket Hole Jig. This would have been my preference if we had one in our tool arsenal.

Now attach the bottom piece to the side panels. Please note that the baseboard trim will be attached to the bottom piece so you'll want to adjust the height according to the height of your baseboards.

Eg; we have 4-inch baseboards so the bottom of the bookcase is attached 4-inches up from the bottom of the side panels.

Building a custom built-in bookcase with 3/4 inch pine boards in a master bedroom.

To add stability to the bookcase and ensure that it is perfectly square, we installed a stationary 12 x 23 1/2 inch pine shelf (pictured above) in the middle of the bookcase. It is attached with wood glue and #8 1 1/2-inch wood screws exactly the same way the top and bottom pieces were installed.

Attaching Bookcase To Wall

Now we're ready to attach the bookcase to the wall and you'll need a second set of hands and some wood shims for this step. The floor will likely not be level, especially in an older home like ours.

  1. First, attach two 1 1/2-inch metal angle brackets on the top of the bookcase.
  2. Then set shims on the bottom of the bookcase accordingly until it is perfectly level.
  3. Mark the holes on the angle brackets onto the wall with a pencil.
  4. If you were not lucky enough to hit a stud where the pencil marks are on the wall, install drywall anchors and screw the bookcase onto the wall.

Crown Moulding And Baseboards

Last but not least, install 3-inch crown moulding with brad nails along the top edge of the bookcase as pictured below.

Installing crown molding on the top of a built-in master bedroom bookcase.

Install the baseboard trim with brad nails along the bottom edge of the bookcase. Run a bead of white latex caulking where all the edges meet the wall. This makes it look more finished and built-in and further provides stability to the unit.

All the exposed screw holes on the bookcase, window seat, and small shelving unit are filled with a non-shrinking filler and sanded once dry.

Then with a foam roller, it was primed first with Zinsser Bullseye 123 Primer followed by two coats of white satin Behr Paint & Primer For Cabinets And Trim latex paint.

Priming the bedroom window seat and bookcase build.

Now all the window seat needs is a comfy cushion.

Painting the bedroom window seat with white latex paint.

I made a custom window seat cushion with 3-inch upholstery foam and drop cloth fabric. Sorry, but because this post is already so long, I am not including a tutorial.

Drop cloth fabric cushion for the top of window seat in master bedroom.

On the window seat are two handmade throw pillows and you can find the tutorials for those in my DIY turquoise rosette pillow and DIY pearl envelope-style pillow posts.

I need to fill the bookcase with stacks of books to enjoy while relaxing in this cozy bedroom reading nook.

A handmade window seat under a large master bedroom window with flanking built-in bookcase.

I have to admit that I was concerned adding a built-in bookcase and window seat would make the master bedroom look smaller. But to my delight, it actually makes the room feel larger! A lot of it can be attributed to the natural light coming from the new window.

Master bedroom with built-in window seat and flanking built-in bookcase.

I should mention that the headboard pictured above is also a DIY project that we made for our master bedroom. We turned an old 5-panel solid wood door into a DIY mantle ledge headboard.

What We Should Have Done Differently, oh my!

Now here's where I'm going to keep it real. This is a prime example of making the mistake of putting form before function when designing a space.

It didn't take long to realize there were some flaws in our original design. Despite having mapped out the window seat on the floor, sitting on the real thing proved to be much different!

With this being a well-used space with much-needed storage in our small 1960s master bedroom, we couldn't ignore the fact that the DIY bedroom window seat needed a makeover.

Can you spot the changes in the photo below after the makeover?

Master bedroom window seat makeover to fix flaws in the original design.

Here's a photo of the original DIY bedroom window seat and bookcase to refresh your memory.

Master bedroom window seat before getting tweaked with a makeover.

The modifications are subtle but made a HUGE difference to the comfort, storage potential, and aesthetics.

Problems With DIY Bedroom Window Seat Design

There are four problems with the original window seat design and I've outlined them below. Then further down I'll explain our solutions for each of these design flaws.

Problem 1: Window Seat Depth Too Narrow

Worried the room would feel cluttered, our focus was that the window seat accommodates a 36-inch gap between the seat and the bed. What we didn't anticipate was that unless you were a child or a petite adult (in my dreams), the seat depth was uncomfortably narrow.

Problem 2: Limited Storage Space Under Window Seat

We were lucky if we could fit more than one blanket in what was supposed to be valuable linen/blanket storage under the window seat.

Problem 3: Electrical Outlet Placement

What were we thinking! Even though we hardly used the plug on the window wall, we never should have left it INSIDE the window seat. Turns out we use it more than we thought and what a pain trying to plug something in. Let alone that it wasn't to code.

Problem 4: Choppy Sightline

When all was said and done I did not like how choppy the window seat looked not being the same length as the window. However, I did like having a small built-in shelving unit on the right-hand side of the seat. While made to match the built-in bookcase on the left, it looked disjointed.

DIY Bedroom Window Seat MAKEOVER

In order to remedy the four problems with our original design, we dismantled the window seat and small shelving unit and started over again. But this time with a much smarter design.

Removing the old custom bedroom window seat to give it a makeover.

Bedroom Window Seat Makeover Supply List

3/4 x 16 x 72-inch Laminated Pine Project Panels
3/4 x 16 x 36-inch Laminated Pine Project Panels
MDF 1/2 x 1 1/2-inch Casing Trim
Piano Hinge
Locking Lift Up Lid Hinge
5 6-inch Wood Furniture Legs
#8 1 1/2-inch Wood Screws
#8 2 1/2-inch Wood Screws
Wood Glue
Zinsser Bullseye 123 Primer
White Satin Behr Paint & Primer For Cabinets And Trim
Foam Roller
Serrated Bread Knife (cutting foam)
2-3 inch Upholstery Foam

Bedroom Window Seat Makeover Dimensions

Window Seat: 60" wide x 19" high x 18" deep
Window Seat Top: 60" wide x 21" deep
Window Seat Side Cubby Unit: 25" wide x 19" high - Depth is angled 18 to 12-inches 

Solution 1: Increased Window Seat Depth

Moving the bed over six inches gave us the necessary space to increase the depth of the window seat. Increasing it by just three inches made the seat far more comfortable.

To accommodate the extra depth, the back plate behind the lid is now five inches, making the total depth of the window seat 21-inches.

We also changed the decorative trim on the front with a simple MDF 1/2 x 1 1/2-inch casing instead.

Modified bedroom window seat to increase seat depth.

Solution 2: Increase Window Seat Storage Space

Rather than the original bulky 2" x 3" frame lined with hardboard, we rebuilt the window seat with just the 3/4-inch laminated pine. This removed the bulk and provided a lot more storage potential.

Modifying a bedroom window seat to increase storage potential underneath.

Solution 3: Electrical Outlet Moved For Easy Access

The electrical outlet was moved just above the window seat for easy access. It can be hidden with throw pillows when not in use.

Moving electrical outlet above window seat in master bedroom.

Solution 4: Clean Sightline

By modifying the small shelving unit to the same height and leaving it open underneath, it now echoes the window seat. I like the clean sightline much better than how we had it before.

Built-in window seat cubby in master bedroom.

You can see in the photo above that the cubby is made with 3/4-inch MDF and that is because we ran out of pine boards.

The cubby is angled because the closet is to the immediate right so we had to narrow the depth in order to be able to open the closet doors.

You may be wondering in the photo above, why we didn't angle the top of the cubby so it is flush with the window seat lid. When we tried that, it looked odd because the top angle didn't match the bottom.

In hindsight, it would have been fine because when I cut the foam for the cushion flush with the window seat, it look good.

Two inch upholstery foam cut for top of bedroom window seat.

It took three attempts to find just the right upholstery fabric. The first two choices won't go to waste as I'll use them for future furniture makeovers. The winning fabric was on sale for 75 percent off, so I don't feel bad about my indecisiveness.

Bedroom window seat makeover with custom seat cushion.

Unfortunately, I didn't have enough fabric to make piping along the edge of the cushion but I'm okay with that - less work. As it was I must have taken this crazy cushion cover apart three times before getting the angle right.

Built-in cubby for open storage on master bedroom window seat.

We are so much happier with our master bedroom window seat now and what I love most about the makeover, is that the cushion extends the entire length of the window. The time and effort we put into the modifications were so worth it.

The night table pictured below is an inexpensive box store table makeover that used to be an espresso color. Not pictured on the other side of the bed, I turned a beat-up legless drawer unit into a gorgeous DIY metallic nightstand.

Custom bedroom window seat with built-in bookcase in master bedroom.

A lot of DIY projects went into the transformation of our master bedroom. When you consider what it looked like in the before photo that I shared earlier, the difference is night and day!

Even our nine-drawer dresser that we've had for over thirty years on the opposite wall got a farmhouse-style dresser makeover that is more fitting with the new aesthetic of the master bedroom.

Because we did all these projects ourselves, the master bedroom makeover was completed on a small budget.

Thanks for stopping by the Interior Frugalista today! I hope you were inspired by the DIY master bedroom window seat and bookcase, even if it took a second attempt to get it right.

Almost all of our DIY ideas have step-by-step tutorials so why not get your budget DIY on and subscribe. You can also find us on Pinterest, Facebook, Instagram, and YouTube.

If you have any questions, please leave them in the comment section below or the Contact Me tab at the top to drop me an email. I love hearing from you!

If you enjoyed the DIY bedroom window seat makeover, I'd be so thankful if you shared it with a friend and pinned it to your favorite board on Pinterest.

How to build a DIY bedroom window seat with storage underneath and a custom built-in bookcase for a master bedroom. Plus how we gave it a makeover to tweak some design flaws. #diywindowseat #diybuiltinbookcase #bedroomideas

I share my projects at these inspiring link parties.



  1. Marie that was one difficult project! But so worth it. The window seat is modern and beautiful and looks very cozy indeed!!

    1. Hi Mary, thank you so much! Surprisingly, being such a large project, we got it done over two weekends. It's become my favorite reading spot in the entire house.

  2. Bravo Marie. This is so fabulous. Looks so great under your larger window. I wish our Thanksgiving was earlier like yours sot there would be a little more time between Thanksgiving and Christmas here in the US. We just get through Thanksgiving the last Thursday of November and then it it the downhill slide right into Christmas. Enjoy and Happy Thanksgiving. xoxo Kris

    1. That's too funny Kris because when Thanksgiving snuck up on us so quickly I said to my husband that I wish it was later, like you guys in the USA. LOL

  3. This looks amazing under your bigger window. Bravo what a great job. I am not sure my first comment went through so here I am again lol! Happy Thanksgiving to you and your family. I wish our Thanksgiving here in the states was sooner and not always the last Thursday in November. Right after Thanksgiving is the down hill slide into Christmas. Just wish we had more time in between the two big holidays. Enjoy. xoxo Kris

  4. Marie, your bedroom makeover is gorgeous. Such a peaceful place for reading and rest. I love the color you chose. Thanks for sharing.

    1. Hi Felicia, thank you so much! The color sure helped create a calming space and I love it paired with all the white elements in the room.

  5. I love your window seat -- the final version. The first was nice, but I'm with you, the seat cushion looks so much better the full window length. My admiration to you for your willingness to not settle and make the extra effort (I'm sure lots of work!) to make it exactly what you wanted. Wishing I had a husband who was willing to do those same kinds of DIYs -- as well as the necessary tools.

    1. Thank you! My heart sank when I realized the window seat was too narrow but I'd been waiting for a window seat for so long that I just couldn't leave it as is. Then I figured it we had to take it apart, may as well address the other things I didn't like too. Yes, I feel very pleased to have a handy husband who is willing to take on my crazy DIY ideas.

  6. The makeover of the makeover is great and I would have done it also. Love that fabric on the bench.

    1. I'm glad you agree Carla! My heart sunk when I realized the seat was too narrow but I just couldn't leave it as is. Figured since we had to take it apart, may as well address the other things I didn't like while we were at it.

  7. Let there be light!! Oh my goodness, Marie. I need a deep breath after ready all your work. oy! You guys did an AMAAAAZING job. And, I love that you shared what you changed on top of it all. Now grab a cuppa and enjoy the view!

    1. It sure was a lot of work in the end but surprisingly only took two weekends to get er done. It's the perfect spot for a cuppa and a good book but oftentimes I end up just watching the antics of the squirrels, birds, and other wildlife that come into the yard.

  8. Just beautiful Marie! I want to come back in my next life as another you... you are so incredibly talented! This was an amazing project and the end result is simply gorgeous. Thanks so much for sharing. Pinned!

    1. Oh gosh Denise, the feeling is mutual! xo I'm glad you like our bedroom transformation and thank you for the pin. 😊

  9. Wow! This is just amazing! I am so impressed by the transformation. I'm visiting you today from the Farmhouse link-up. God bless you this autumn season! :)

    1. Thank you very much, Cheryl, I'm glad you like the bedroom transformation and thanks a bunch for popping over from the link-up!

  10. Wow Marie I am so impressed (as usual) with how incredibly talented you are! I love how the window bench and shelving units came out. Good call on the storage. It was a lot of work but it was so worth it. Your update bedroom looks great. Pinned! Please come and share at my Home Imagined Link Party on Tuesday 9am- Thursday 5pm. Have a great weekend-Meagan

    1. Thank you so much Meagan! I am so happy that we modified the storage underneath because I fit quite so much more in there now. See you on Tuesday at your party!

  11. What a challenge! And I have to say that the final outcome is perfect for the room. Thanks for sharing all of the details, the good and the bad, and the reason why you made some changes. I am excited to feature your post at the next party. Welcome back! #HomeMattersParty

    1. You made my day, Donna, thank you so much for the feature! xo

  12. Wow, Marie. That looks amazing. It changes the whole room. Amazing job as always and I'm so happy you're sharing your unique talent again. I missed you

    1. Thank you very much, Michelle 😊 What a difference a new custom window made to this space and we love it!

  13. Marie, congratulations! You will be featured at the Home Imagined Link party on Tuesday!-Meagan


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