Build a Window Seat With Storage





Introduction: Build a Window Seat With Storage

What's a bay window without a window seat?  An unfinished and underutilized space waiting to be transformed!  Building a window seat is a basic "build-in" project and here's how you can do it.    

Step 1: Plan It Out

Since bay windows are not all created equal, you'll need to measure the angles of the walls.  The standard is 135° but there are other variations and the "as built" angles will probably be different.  Walls are never perfectly straight, corners are never perfectly get the picture.  In the end, you don't have to be super exact since a piece of trim will cover the gap between the wall and the seat, but the angle needs to follow the wall.

How deep you'd like your seat to be is the next question.  I build this one to be 24" deep so we could use a rug runner instead of cushions.  Runners are 21"-23" wide.  How deep your seat is will also determine how wide it will be.  At 24" deep, mine turned out to be 8' 5" long.  Since sheets of plywood are 8' long it would have been easier to make the front shorter than 8' long and let the depth work itself out.  In that way you could rip an 8' piece of plywood for the front whereas I used 2 pieces.    

On I found a sketch of the framing for a window seat (pic 2).  The height they recommend is 19" with a 21" deep seat.  You can see from the drawing that a window seat is actually a short floating wall achored to 2x4 cleats on the wall.  The front can be wood, sheetrock or other materials since it is only decorative.  The one thing I did differently from the drawing was to place the 2x4s on edge as opposed to typical wall framing.  This makes a sufficiently strong wall and also creates a bit more storage space inside the bench.  

Step 2: Supplies You'll Need.

Your vision of how you'd like your window seat to look will also determine the supplies you need to acquire.  The possibilities range from basic plywood  to sheetrock to expensive trim to reclaimed wood.  The basic frame, however, will not vary greatly and I used two 10' 2x4s and four 8' 2x4s.  For the front, I used a 4'x4' sheet of bead board and around 24' of 1x4 poplar for the trim.  One 4'x8' sheet of 3/4" plywood is more than enough for the top.  3/4" is the minimum thickness for the top since people will be sitting on it.  To strengthen the front edge of the top, I ripped 1 1/2" poplar strips from 3/4" thick stock on my tablesaw.  To finish the junction of seat top & wall, I used 12' of 3/4" cove molding.  And lastly, 3/4" quarter round was used along the bottom of the front and a couple short pieces of baseboard were also necessary to finish the trim. 

Other things you'll need for this project are construction adhesive (Liquid Nails), silicone caulk, wood putty, sandpaper, primer, paint, 3 1/2" wood screws and nails.  A trim nail gun and air compressor are ideal and worth renting if you don't have them.  A miter saw is also very nice for the many angle cuts.  In addition, you'll need the usual carpentry tools such as a level, stud finder, hammer, nail punch, circular saw, etc.  

You'll see as we go along that I used pocket screws for constructing the 2x4 frame and also the poplar trim.  Pocket screws are a quick and easy way to make strong tight joints and are applicable to virtually every type of woodworking.  If you aren't using pocket screws, check out and join the fun!

I don't hate painting if painting is my project (e.g. paint the kitchen).  What I hate is building my project and then having to paint it.  I get that "You did it!" feeling and then realize I have to paint it.  To remedy this problem I paint before I start my projects when possible.  While I'm scratching my head and measuring and figuring, I run to the shop periodically to lay down a coat of paint.  It only took me about 30-45 minutes to paint the boards and plywood each time.  As it dries, I go back to scratching and starring blankly at the walls.  When the project is built, just dab some wood putty in the holes, touch up the paint and you're done.  It is so much easier it's insane.

Step 3: Building the Frame

To begin framing the box, use a stud finder to locate the studs inside the wall.  Normally studs are 16" apart on center, however, there is likely to be some variation under the windows.  With the stud locations marked, mount a 2x4 along the back wall using 3 1/2" wood screws.  The top of this board is 18 1/4" off the floor so the final height will be 19" when the 3/4" plywood is added.  Make sure the 2x4s mounted to the wall are level.  There is no reason to miter the 2x4s in the corners as there is no benefit to doing so.  These ends will be hidden from sight and mitering the ends would have no effect on strength.

The next step is to remove the baseboard and build the front wall frame.  I chose to build the wall next so I could insure it was parallel to the back wall.  Alternatively you could mount the other 2x4s on the side walls, however, this seemed a simplier way to determine where the wall would actually be located.  Both the top and bottom 2x4s have 45° cuts on both ends to match the wall.  The front wall is only 18 1/8" tall so shims could be placed underneath it to bring it to level with the wall mounted 2x4.  True to form, my floor had a crown in the middle and it was necessary to shim both ends.  

My design was for 4 front panels so I placed five 2x4 blocks in the front wall.  These blocks are located behind where the poplar vertical trim pieces will be which allows for nailing.  I'm not sure why I didn't have the furthest left & right blocks all the way at the ends of the wall, but I ended up adding a block on each end for trim nailing (pic 3).  Note the pocket screw holes in the blocks.

The final steps are to add the 2x4s on the side walls and add some bracing for the top.  The side 2x4s have a 45° angle on the front end so it can butt up to the front wall.  Once they are screwed to the walls using 3 1/2" wood screws you can also place screws through the front wall and into the side 2x4s to lock the corner. Three 2x4 were installed between the front and back walls using pocket screws.  The middle 2x4 is centered and the outer 2x4s are located where the end of the lid will rest.  

Lastly, this is a very good time to reinstall the baseboard & quarter round on the inside of the box.  

Step 4: Building the Faceframe

For a project of this size, I find it easier to build a faceframe in my shop as opposed to installing each board individually.  Although it is not important in this case, faceframes also add considerable strength.  I build the faceframe to be 18" tall to accomodate the floor crowning which made the stiles (vertical pieces) roughly 11" long.  When this is installed, any gap will be along the floor and covered by the quarter round.  Since the faceframe is shorter than the wall, it can be lifted flush with the top of the 2x4s before you nail it.

Picture 2 shows the finished faceframe.  Doesn't it look nice painted!!  You may also notice that the 2 inside rectangles are slightly smaller than the outside rectangles.  This is by design to make the box look less symmetrical and "exact".  When something you build is very precise and regular, it doesn't look natural.  Nature is much more random than it is regular which can make a large symmetrical piece appear odd and less pleasing to the eye.  When I have the opportunity, I try to add a bit of asymmetry to projects.  No one will be able to tell you why they like it better, but they will like it better.

Step 5: Cover the Front Wall

Now that the faceframe is ready, it's time to cover the front of the box.  I don't have pictures of this step but it's very straight forward.  Apply a bead of Liquid Nails construction adhesive to the front of the 2x4s and nail the beadboard/plywood to the 2x4s.  The only edge which will be visible is along the top lip so position the beadboard flush with the top of the 2x4s.  Installing the faceframe is essentially the procedure.  Run a bead of Liquid Nails on the back of the faceframe and nail it in place.  Fill the nail holes with wood putty and caulk the seams with silicone window caulk.

Step 6: Building the Window Seat Top

The top of the window seat is comprised of 4 pieces of 3/4" plywood with a 1 1/2" strip of trim along the front edge.  Pic 2 shows the shape of the pieces.  I began by cutting the rear piece which is 5" wide with 45° angles on each end.  After a bit of trial and error, I found 5" to be sufficiently wide to allow the lid to rest against the window and remain open.  This piece could be wider, but not much narrower or the lid will fall down all the time.

Next I measured the distance from the front edge of the 5" piece to the front of the box to get the width of the lid.  Since the piano hinge requires almost 3/16" space I cut the lid to 19" which was the actual distance measured.  This gave me 3/16" overhang on the front of the box when the hinge was installed.  I chose to make one large lid, however, you could easily make two.  Alternatively, you could also make a solid top and doors on the front.  In this case, I made one lid which extended to the center line of the outside 2x4s.  In this way, the side edges of the lid rest on the 2x4 for support.  The lid measures 19" x 51".  

Before you glue & nail the 5" back piece in place, it's much easier to go ahead and attach the lid to it.  This is a job you don't want to do from inside the box.  Picture 3 shows how a piano hinge is attached.  A piano hinge is a long continuous hinge which is very strong and a perfect solution for this project.  PIano hinges commonly come in 30" and 48" versions and 48" would have done the job.  I chose instead to use two 30" hinges so the entire gap would be filled.  This was easier than mortising a space for the 48" hinge.  Piano hinges can be cut to the desired length using a hacksaw or portable grinder.  The hinges I used have sides that are 3/4" wide so I mounted them flush with the bottom of the 3/4" plywood.  In picture 4 you see that the hinges protrude a small bit but it's not noticeable when the rug in laying on top of it.  

With the 2 pieces hinged together, there's a couple things that need to be done before permanently attaching them to the box.  First is to mark out and cut the 2 smaller side pieces.  This is most easily accomplished with the lid & back piece in place so you can measure size.  Leave a 1/16" gap between the lid and the side pieces in case the wood expands.  Plywood doesn't move much but a little gap is needed.  Once the side pieces are cut, the second thing is to attach the 1 1/2" trim to the front of the lid and 2 side pieces as in picture 5.  Some wood glue and nails is sufficient.  

Now put it all together with some Liquid Nails and some solid nails.  Lay down a bead of Liquid Nails on the 2x4s which are under the 5" back piece and nail it in place.  Then do the same with the 2 side pieces.  Make sure to avoid getting the adhesive under the lid --especially when positioning & nailing the side pieces.  The last picture is the 3/4" cove molding along the top edge of window seat.  I like cove molding here but you could also use quarter round or a larger piece of trim.  

With everything in place it's time to touch up the finish by filling nails holes with wood putty, caulking the seams and giving it another coat of paint.  

Step 7: All Done!

I hope this instructable has been helpful to you.  A window seat is pretty easy to build for such a large project and there's a lot of bang for the buck too.  In it's simplest form, this seat can be built for around $100.  Mine was a bit more because of the poplar trim and bead board on the front.  Regardless it's been worth every penny and it's great to have some extra storage in our kitchen.  

Thanks for looking!  I look forward to any questions or comments.

3 People Made This Project!


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I took the base of your plans and added a little extra. Thank you for all of the help!!

1 reply

Very nice! Glad the plans were helpful.


Great instructable! I'm looking forward to start making one of these for my own house. One question: do you find the center 2x4 essential? I realize it provides support, but I don't like the way it puts a beam in the middle of the storage space. Would using just 2 2x4s and possibly a thicker board for the top provide enough strength for one or two people to sit on it?

1 reply

Thanks! I think you need it or need to add strength with a thicker top as you suggested. You could also make 2 smaller doors between the 3 2x4s as they are currently arranged.

Great post! Any words of advice on a curved bay!? Really want a window seat but unsure on how to start with a curved bay ?

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Cutting the top is the trickiest. What I would recommend is to cut a piece of cardboard an 1" smaller than you need and tape it in place so there's a gap. Then use stiff card stock strips to bridge the gap and tape them to the top of your cardboard. This lets you make an exact copy of the wall and any of it's quirks. Lay that facedown on the back of your top and trace the outline and the should match very closely especially with trim. For the trim, the easiest is to use vinyl trim since is bends easily and you won't need to make relief cuts. Can you post a pic of the curved bay?

Great job! Looking forward to a starting a window seat of my own. This is a BIG help.


Great job! Looking forward to a starting a window seat of my own. This is a BIG help.


I've always liked the idea of sitting at a window seat with a whiskey and a cigar and the fact that it'll double up for a storage unit is a pretty awesome idea too. Not to mention I think a lot of wives and daughters will really like to curl up and read a book in the corner somewhere. Definitely a project for the home to consider sometime in the coming year!

Storage is always welcomed around the house regardless of the size. I have utilized almost every inch of my apartment including the walls and ceiling to their maximum capability to maximize space as much as possible. I have also tried clearing out some closet space for the sheets but there are just too many. This window seat with storage looks perfect even for the rooms.

I've been looking at this project. What is the need or reason for the 2 X 4 in the center where the lid will close? I'm just wondering if I want to put in longer items in here? Is it structural? A way around it?

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It's structural. The framing gives support to prevent sagging when someone sits on it. It also supports the lid and provides it a place to close. You could run another 2x6 down the middle length wise and block it to the back. The back half would be solid and the front half a hinged lid.

love this post! I'm considering taking up this project in summer. My house is carpeted. so should i rip off the carpet under the seat or build the seat over the existing carpet?

2 replies

I'd rip the carpet out. You won't have to worry about the it deteriorating over time or keeping it clean. The base should be front should be setting on solid floor and not carpet as well.

If it's carpeted you might want to rip out the carpet but don't take my word for it.

hi, love these instructions! I have been working on my window seat, my first real woodworking project, and hoping you can tell me how you end your moulding on the front edges? Thanks!

1 reply

Thanks! Glad instruct was helpful. The molding around the top edge is cut flush with the top but could also angle back at a 45.

I love the idea of window seats that incorporate extra storage space for random stuff lying around the house. And it always pays to have an extra corner or something to keep things out of sight!

Thanks for the excellent tutorial - I never would have made this otherwise. I thought I'd share a few lessons I learned along the way, probably lessons mostly useful for the novice like me rather than the experienced DIYer.

Firstly, I had lots of 'slightly-thinner-than 2 by 4' timber left over from a previous project miscalculation. It's about an 30mm wide, and I was concerned at first this wouldn't be strong enough or might make aligning the top of the lid fiddly, but it worked out fine and it seems plenty sturdy enough for 3 or 4 people of average weight to sit on it. My only concern would be the pocket joints on the back to front bracing pieces, but mainly because I don't have much experience of them (bought a jig specially for this) so maybe I'm being paranoid. Definitely get a pocket hole jig if you don't have one - I bought just the jig for about £5.50 if you don't want the much more expensive whole kit and caboodle. As long as you have a clamp you don't seem to need the rest so I'm not sure I get why there expensive kits out there? Someone will let me know I'm sure.

Allow plenty of room for the extra depth that making panels will create. I used 12mm MDF, with 12mm MDF panels, so that's 24mm extra depth right there. Sorry if that's an obvious thing to everyone but, hey, I didn't add it on in my calculations! Maybe because it wasn't obvious in the design sketch above so I ended up slightly closer to being flush with the bay than I had intended.

I had originally added a profiled pine trim to the lip of the lid and the seat - see it in the third picture if you look closely. However, this inadvertently led to the lid having a kind of sharp 'blade' that would be sure to do some serious damage to any little, or even big, fingers trapped in the lid. I reluctantly tore it off and used a flat profile 18mm thick strip of rectangular profile pine (to match the 18mm thick MDF lid) and this is much much safer. See picture 4. I was worried it would look chunky and out of place but it doesn't, it looks just fine.

It also makes finishing off the corners where the mouldings all meet much easier - see close up (which still needs some touching up on the grey paint!).

The unanticipated depth of the panels meant it was more sensible, I think, to work 'backwards' from the front of the seat to the back, as any left over gaps at the back of the seat were easy to cover with trim. I wondered though if in any case it would be more sensible to work backwards from the front, as this way you are guaranteed a perfect fit at the front where people will see it.

A tip on the piano hinge - the one I bought was fairly cheap and had not much 'indent' for screws to sink in to it's depth - as the screw holes on each 'flap' of the hinge lined up with each-other there was a risk that the screw heads would bump in to each other when shutting the lid, so it wouldn't lie flat and flush. The simple trick was to only screw in on alternate holes, so the screw heads never met - it seems plenty strong enough still.

The 18mm MDF is quite heavy - even this relatively small seat has a 1m wide lid which makes a room shaking slam if it falls shut. I 'borrowed' some Blum soft close door dampeners from my kitchen where there are 2 on every door - it turns out you only need one on each kitchen door for the exact same soft close effect so they were effectively spare. Even though they are very stiff, I need 3 on each side of the lid to be an effective little finger saver, and even then it won't prevent a smack on the knuckles, though I daren't try it. Adding the soft closers takes some fiddling - drill a hole though then for a screw hole, and position 2 near the hinge and one about half way down - this seemed to be optimal for my lid, but you mileage may vary. Warning: the momentum of the falling lid is pretty large so the lid will feel a force to 'pivot' on the dampers, effectively stressing and pulling 'up' on the back-most piece of the lid that holds the hinge in place, so make sure that has plenty of screws holding it down securely. While I did consider using 25mm MDF for the top, 18mm seems just fine and I can't imagine any amount of damping would hold a falling 25mm thick lid.

Finally, if you have shutters like those in the picture, I found that using a small round cushion at the back helps to stop people accidentally shutting the shutters by leaning back too far! Not ideal when you are trying to soak up the sun.

Thanks again for the instructable, I couldn't have done it without you.

1 reply

Beautiful! Nice job! Thanks for sharing!