Modular Bookshelf




About: I'm a carpenter/brewer/woodworkshop-teacher/musician from switzerland. For as long as I can remember, I was making stuff. Due to my professional education as a carpenter I have a lot of background knowledge ...

I wanted to build a good-looking and practical bookshelf for our new apartement. Since the apartement is on the top floor, the ceiling is angular and the bookshelf had to be fitted to the wall. I decided to design it in a modular way, so it can easily be adapted to different circumstances. It took some thinking and tweaking, but I came up with a solution that works rather nicely.

There are some big advantages (in my opionion):
- You can rearrange the whole thing whenever you get tired of looking at it
- It's easily expandable (by either rearranging or building more modules)
- It creates a "living" wall of books (and/or other things)
- The modules are very light and are easy to move around, plus they take up very little space (for example in a moving van)

Step 1: Design

The modules come in different sizes (either quadratical or oblong).
The width is in every case a multiplate of the height (up to 5:1 in my case), so that the modules are stackable. There are 3 different module-heights to accomodate either paperbacks, hardbacks, binders, big books, and so on. The different sizes of books/binders demand different depths for the modules, too, which gives a really nice look to the complete bookshelf.
The longer modules (3:1 and more) need a middle panel, to distribute the weight of modules on top of them evenly.
In order to combine all these different heights and widths, I had to build 2 customized modules which have different sizes (to adjust for the height), but besides that, everything is standardized.

I wanted to build the modules as low-key and sleek as possible. There is almost no hardware needed, since all the joints are glued. The mitred joints allow for a very elegant construction (although its harder to build) and keep the whole design very simple.
To assemble the whole bookshelf I made aluminum-clips out of a U-profile. Lined with textile tape, they clamp together the modules, making the whole bookshelf stable and sturdy.

Step 2: Materials and Tools

For my bookshelf I chose a 9mm phenolic resin-coated birch-plywood. This coated plywood has a very robust and nice looking surface, but it is rather expensive (about 48 US-Dollars per m2). Plywood offers the advantage of constructing this with quite thin material (9mm), and there is no real need for the coated surface besides the look.

Since I don't own equipment to cut the big boards down to size, I had the material ordered as strips of the 3 different depths I needed. Clean and nice cuts are really important, since half of the edges are visible at the end.

So the needed materials are:

- Plywood-strips (widths depending on the measurements for the modules)
- Aluminum-U-profile (to produce the clamps)
- Felt-pads for the bottom modules

The tools I used for this project:

- A halfway decent circular saw bench (with the ability to tilt the saw blade to 45 degrees)
- A calibrated try square
- A measuring tape
- Lots of abrasive paper
- A very well sharpened chisel
- 1-K PUR wood adhesive (it has to be a really strong adhesive, since the surface of the connections is quite small)
- Plenty of plastic adhesive tape

Step 3: Cutting

The first step is cutting the plywood-strips to the required lengths. To achieve very clean cuts, I use a piece of thick plywood as a base, on which I cut the miter joints (and even joints for the middle panel). This way I get close to no chipping at the edges.

It is very important to use arrestors, so that the corresponding pieces have the exact same length. I tend to check the lengths after every second cut, just to be on the safe side.

The angle of the sawblade is crucial, since even a half degree off can result in joints that don't fit properly. I use surplus wood to test that angle very carefully until the pieces fit perfectly.

Always take care to use the safety devices as specified! Even if it means slower progress.

Step 4: Sanding and Preparing for Assembly

The surfaces of this coated plywood don't need to be sanded, but with other materials, now would be the time to get a nice smooth surface.
To get the edges nice and smooth, I take several pieces of the same width and pinch them together with wooden bar clamps. It's easier to work this way and ultimately, it's a lot faster.

After sanding all edges like this (a very important step) I chamfer the edges very subtly. I prefer sharp edges, but still, they should be a bit chamfered.

When all of this is done, the pieces should be cleaned. All the dust needs to be removed, as not to affect the quality of the adhesion.

All the joints (inside and outside) need to be prepared with plastic adhesive tape. This technique will take a moment to prepare, but the time it saves after the adhesive has cured is substantial. Align the tape very carefully on the very edges (inner and outer edges) and do this wherever there will be adhesive (as seen in the pictures). Do the same for all middle panels by measuring precisely where they will be and then taping around the adhesive surface. The overspilt adhesive will cure on the plastic and can then be removed very easily.

Step 5: Assembly

Now it is time to assemble the parts by means of plastic tape. Place the pieces in the right order on a flat and clean surface and tape them together on the outside. Its very important that the outside edges are perfectly aligned so the miter joints will fit. When everything is taped together on the outside, it has to be flipped, which can be quite tricky. Now it is possible to "fold" the whole module and check if everything fits nicely.

I always do this before I apply any adhesive!

After this check, I apply the adhesive. The adhesive I use expands while curing, so not much of it is needed in these joints. If there is excess adhesive, don't bother wiping it off. PUR-adhesive is really nasty before curing and can much easier be removed mechanically after curing.
After applying the adhesive, I "fold" the pieces together and fixate both "open" ends with more plastic tape. I use a try square to check the angles and check all the corners carefully because the edges can sometime shift a bit.

Since the plastic tape is also applied for the middle panel (where one is planned), it is convenient to insert this panel at this time. I apply the adhesive on the panel's edges, spread the module a bit and put the middle panel in-between. It's easy to adjust its position because of the plastic tape, and to be sure I check it again with the try square.

When all the angles are checked again, I put some weight on top of the module so that the middle panel receives the needed pressure, check all the angles once more and let it cure for at least 3 hours (depending on the adhesive).

Step 6: Finishing Touches

After curing, all the plastic tape can be removed, which should get rid of almost all the excess adhesive. The adhesive residue on the edges and in the corners needs to be removed very carefully with a well sharpened chisel. The traces of adhesive on the edge need to be removed by sanding, so that the miter joints look nice.

I chamfer the now joined edges a little bit and retouch them with a black marker. This leaves no trace on this material, but needs to be tested with every other material.

I always test the modules by trying to pull them apart, but they are really sturdy. After checking all the edges, I decide which side looks better, and I mark the less perfect side so that I know which way to assemble the whole thing at home.

Step 7: Finished Product

I've had some practice in producing these modules, since I wanted to fill the whole wall with this modular bookshelf. It sounds like a lot of work, but by producing multiple modules at a time, it becomes quite efficient. To produce a single module takes about 1 hour (besides the curing process). Producing 10 modules will take maybe 5 hours, and the more modules are made side by side, the less time it takes.

I enjoy this project a lot, because it's practical and beautiful. Working on it is very satisfying, since all the time spent for preparations really pays off in the end.

I would be happy to read your ideas, your criticism, your opinions and your remarks on this modular bookshelf. Thank you!



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    56 Discussions


    1 year ago

    Would you build one of these for someone for sale? You could ship it ready to be assembled?

    1 reply

    Reply 1 year ago

    Hi BrandiK

    Thank you for the message - I dont have the time to build one of these for sale, i'm really sorry! plus, it would be quite expensive to build and ship.

    all the best, luegg


    6 years ago on Step 7

    What you've made here is a sophisticated-looking set of shelves. The prefinished birch plywood leaves a nice contrast between the edges and the surfaces.
    -- I've done something similar in principle, but as a carpenter, I worked with scraps of 1/2" CDX structural plywood that I got for free, and left them "rustic." My boxes are 12" x 12" x 17" outside dimensions. And my boxes have backs (or bottoms, depending on the orientation) which are set into the four sides-- these provide extra stability, and allow me to use the boxes as moving crates.
    -- A few points I learned from years of experience with these cubes.
    -- First, it's good to have some white cedar shingles around to use as shims, in order to level the base. White cedar shingles have a long taper that allows for precision in leveling, and some of them have very thin tips, for very minor adjustments. Leveling the base can compensate for sloping floors in older buildings or for the so-called "tackless strips" used by carpet installers that make wall-to-wall carpeting thicker around the edges. I usually tilt mine slightly back toward the wall, aiming to touch the wall at the top, despite the width of the baseboard at the bottom. This makes for a more stable setup. I use no attachments between boxes other than gravity.
    -- I decided to use butt joints, because they're stronger in compression. With pre-finished material, there's some reason to maintain the clean look of miter joints, but butt joints, if the edges were finished well, would provide a different, not altogether unattractive look. With unfinished plywood, I used galvanized cedar shake nails, which are thin, about 2-3/4" long, and have rings on the shaft for greater holding power, along with carpenter's glue, and my oldest ones have held up well through about 18 moves since the 80s. I predrilled for the nails only near the front edges of the boxes, where the danger of visible splits was greatest.
    -- I discovered that the flexibility of the system was vastly improved by having an assortment of "planks" made of the same plywood, cut to widths equal to the depth of the boxes (12" in my case), and some narrow fillers cut about 2"x12". When I wanted to go floor-to-ceiling in a wall space 4'5" wide, I placed a couple of boxes on the floor spread to the outer edges of the space, and then laid a plank across the gap, covering, say, the left box entirely and extending onto the right box however far it would reach, and then stuck a filler on the right end of the right box, so that the next layer would have a level base. These gap-filling "planks" allow me to fill up a wall space that's 4'5" wide with two stacks of 17" wide boxes instead of three, and to fill it precisely. This allows more shelf space with less work building boxes. About 50% more shelf space.
    -- I've since begun to make crates that are 9-1/2" deep x 10-1/2" high x 17" wide. When I first began, I made them 12" deep for the sake of stability in tall stacks, but they were so much more stable than I expected that I decided to cut down on the wasted space in each box. Besides, with the planks, I can use a layer of boxes vertically oriented for taller books, and it integrates fine with the rest. And I've begun to paint them, too.
    -- Your system is a lot slicker and more attractive (though I still think putting backs on them would make them stronger). My priority is capacity and flexibility, because I have about 8,000 books to shelve and to move occasionally. One aspect of milking 50% extra shelf space out of my crates is that when it comes time to move, the number of boxes I have fits the number of books, because packing for moving crams a lot more books into a box than shelving books for residential accessibility.
    -- I made my backs/bottoms fit within the 4 sides of the box, and assembled them first as "U"-shaped units consisting of a bottom with two short sides nailed to it, and then the long sides covered the "faces" of the "U." Since the boxes are mostly laid horizontally, this makes the strongest box with the most stable platform for the next layer in a stack.
    -- Sorry for the length of this comment.

    6 replies

    Reply 2 years ago

    bo88y, this is a very helpful comment! What do you think of the idea of making an quick instructable?

    I can imagine what you're saying, but a few pics would go a long way toward helping us avoid mistakes.

    I'm going to make shelves like this for my daughter, (though i don't want to invest in this pretty product), so my version will tolerate the look of the butt joint.


    Reply 6 years ago on Introduction

    Thank you very much for this input! It's always nice to hear from a fellow carpenter. ;-)

    I chose the miter joints not only for aesthetics, but also because I'm used to them. I used to work in a carpenter's workshop where everything had to be miter joints (no matter what angle). Time will tell if I'm over-optimistic, but I have no worries about the stability of these modules.
    I spent quite some time thinking about backs/bottoms, but I really enjoy the look of these "empty" boxes with the plaster behind them. True, it would be great for moving (and the stability), but I have to say, i prefer this look and so I just won't move anymore! :-)

    I would be interested in a picture of these gap-filling "planks", since I'm not sure if I'm imagening it accurately.

    Thanks again and have a nice weekend! Luegg

    PS: (I used to work there; for me it is probably the coolest carpenter's workshop on earth ;-) )


    Reply 6 years ago on Introduction

    The "planks" are just twelve-inch wide strips of 1/2" plywood of various lengths, from about 20" long to about 48" long. I also have a bunch of 2" cutoffs of these strips, which serve as shims. See the diagram, which is the front view of a stack of boxes. The plank on the bottom row of boxes runs from the far left to the left end of the right-side box, while the shorter plank on the second row up is just long enough to sit on the inside corners of the two boxes, and two shims are required, one at either end.

    --- The planks serve as additional bookshelf space, spanning the large gaps between the spaced-out boxes. I could have cut the planks so that they'd run from the far left to the far right and emiminated the shims, but then, I'd have to re-cut them or get new, longer ones whenever I moved and had different wall-spaces to fill. This approach leaves little (1/2" high x however wide) gaps between the ends of the planks and the shims, but I can live with that, and the system is flexible. I can stack the boxes tall and narrow, or low and wide, to fit whatever width of wall I'm filling with books.


    Reply 6 years ago on Introduction

    Ok, i got it. That is more or less what i imagined. That way you can arrange the boxes really efficient. Cool! I try to use the spaces between the modules too, but it was my intention to break up the "lines", so the whole bookshelf has as few continuous horizontal or vertical lines as possible. But of course, that means less available space for books.


    Reply 6 years ago on Introduction

    Your approach has a lot of visual texture and variety, and looks more finished. Mine is more a lazy man's approach motivated by desperation about having too damned many books and, for a while, moving too often. I did get sick of making boxes at one point, and being able to put 90 boxes worth of books in 60 boxes (plus planks) was a relief. Someday, perhaps, I'll get around to painting them. That's about as finished as mine will get. Raw CDX is a pretty "rustic" look, but in the end, when they're filled with books, it's mostly just the edges that show.


    Reply 6 years ago on Introduction

    thanks a lot... I'm working on my next instructables... ;-)


    6 years ago

    That is really nice I like that a lot. Thanks

    1 reply

    Reply 6 years ago on Introduction

    thank you! I'm happy, there are people who enjoy this instructable and design...


    6 years ago

    awesome just today i was trying to billed some like this and was in a lose so thanx for the great and remarkable share


    6 years ago on Step 7

    I have always liked modules for furniture, and this looks good.

    I noticed in the first few photos that some of the units are beginning to sag. This is becase material as thin as 9mm will only span about 12 inches under load. A rule of thumb is that on average a shelf of books weigh 50 pounds per linieal foot. To span some of the distances I see the thickness should be up to about 20 mm. There are variants of this joint, but take more time and more accurate tools.

    Also, I am quite impressed that the wood glue holds to that plastic surface, where the panels are glued in mid-span. I would have made a dado joint where the middle panels are. That way wood would be glued to wood, and the dado will capture the ends of the brace securelt.

    The joints are under a great deal of stress, considering that the horizontals want to sag under load. An easy but strong joint is a spline joint. Just cut a dado in the faces of the joining boards, about 6 mm deep. The joint looks ilke the photo

    1 reply

    Reply 6 years ago on Introduction

    Thank you for these comments. Yes, there are some units that sag a bit. I was considering to build the bookshelf with 18mm thick material, but for my taste, it would have been too massive. Since we own mostly paperbacks I decided to go this way, but there are some issues that have to be resolved the next time I expand this project.

    Yes, that PUR-glue really is impressive. :-) Since the surface is not glossy (it is a little bit rough), there is enough adhesion for these middle panels.


    6 years ago on Introduction

    I love it! Very nice appearance, and more ethical than stolen milk crates. :-)


    6 years ago on Introduction

    I already left a comment, but I can't help it !
    This is not the only "Modular Bookshelf" instructable on this site.
    But I find it rather distinctive by the visual quality of the design : proportions and volume are excellent. This can be seen on the 1st picture of step one where we can see the structure without books. It is an excellent design. Pure, simple no frill… 
    Viewers shouldn't forget the the simplest designs are the most difficult to built to a certain level of perfection as the slightest flaw is clearly obvious.
    The only thing about this instructable that bothers me is 1) the use of a router bit : myself I woul have thought that it would have been easier to make 45° angle cuts with a router. Then again I didn't make it and obviously Luegg managed to get good cuts, so who am I to make such stupid objections ?
    2) the use of polyurethane glue such as 1K-PUR seems somewhat too much to me as the quality of the joint will ensure a tight fix with simple vinyl wood glue which is much less messy than polyurethane. The latter is great for gluing outside or in wet environment such as a bathroom or kitchen. But then again Luegg made it !…
    Again Bravo !!!…

    1 reply

    Reply 6 years ago on Introduction

    Thanks again. I prefer to make these 45° cuts on a circular saw bench if possible. It takes some time to get everything set up and the result depends on the sharpness and quality of the sawblade. But it is much easier to get the exact same lenght for various parts and it is a lot quicker (especially if you want to build 30+ modules).

    What I like about this kind of glue is the fact that it will "correct" some minor faults in the joints. If the angle is a (little) bit off, or the cut is uneven, the expanding glue will correct this to a certain amount. But yes, it is messy and not very eco-friendly. By now I'm really used to working with this stuff and I rarely get black stains on my hands that last for 4 days! And the pictured "container" of glue will last for at least 60 modules. :-)