Build a Bookcase With IKEA BILLY Frames in 8 Steps for 40% More Shelving

Shelf spacing sets the real capacity

A single BILLY frame in the 80cm width comes with five movable shelves and the fixed top, so the 202cm frame gives six usable tiers. IKEA’s normal peg layout leaves roughly 32cm between tiers. That spacing is useful for a mixed collection of paperbacks, hardbacks, and taller books, yet it leaves a noticeable strip of unused air over mass-market paperbacks, which are often around 18cm tall. In many rows the spare vertical space is 8 to 12cm.

A 28mm BILLY shelf takes up its own thickness before the clear space above the books is counted. In a paperback-only bay, reducing the gap from about 32cm to about 22cm allows seven tiers in the height that previously held six. Across three frames, the shelf-count gain can reach the 40% claimed in the title, provided the tighter layout is used only where shorter books are going. Hardbacks and folios still need wider spacing, so the bay plan matters before any extra peg holes are drilled.

IKEA sells extra BILLY shelves separately under the same article number as the spares, usually at around five to seven units of local currency each. The metal shelf pins are also sold in bags, and the standard 5mm diameter matches the pre-drilled holes in the frame sides.

Build the run before filling the bays

Assemble each bookcase flat on the floor using the standard BILLY instruction sheet, then pause before standing the frames upright. Put the three sides together and check whether the pre-drilled peg columns line up from one frame to the next. Particleboard tolerances of a millimetre or two are enough to make shelves look slightly stepped across a 2.4 metre run.

Stand the first frame against the wall and lay a spirit level across the top. Older floors are often uneven, and a small lean at the base becomes visible once the frames are joined and loaded. Shim the low foot with plastic wedges from a pack of furniture levellers before bringing in the second frame. If the case leans, the shelf pins take the load unevenly and the thin back panel can start to bow.

Join the frames through the side panels. Drill 3mm pilot holes from inside one frame into the neighbouring side panel, then drive 30mm screws through the pair. Use two screws at the top and two at the bottom for each joined pair. That connection stops the run from racking sideways, and with the frames acting as one unit, a single wall fixing per frame is enough to stabilise the assembly.

The fixing at the wall is small, but it is not decorative

BILLY includes an anti-tip strap and two screws. Those screws suit timber studs or solid masonry; plasterboard alone is a weak fixing point for a loaded bookcase. The strap is there to resist the forward tip when weight or pulling force is applied high on the frame, including the obvious case of a child grabbing a top shelf.

If the bracket lands over a stud, use the supplied screw there. If the bracket position falls on plasterboard with no timber behind it, do not rely on the screw biting into board. A metal toggle fixing such as a Fischer DuoTec 10 or a GeeFix is a better match for that situation, and both are rated well above the load the anti-tip strap is meant to take.

Mark the bracket height, check the stud line with a detector, and use the top rail to give yourself a little sideways adjustment. When no stud is available at the practical bracket position, fit the toggle rather than leaving the strap on a plasterboard-only screw.

Re-peg only the bays that suit shorter books

Work bay by bay. Trade paperbacks around 20cm tall can sit with about 22cm of clear height above the shelf. Larger art books around 32cm tall need closer to 34cm of clear space, so they belong in a looser bay. Pencil the chosen peg holes before inserting any pins, starting at the bottom so the heaviest books stay on the lower shelves.

The BILLY peg columns are drilled at 32mm centres. A 22cm target will usually land on a nearby hole within about 3mm, which is close enough visually once the shelf is in place. Each shelf needs four pins, two on each side. If one pin is missing or not seated, the shelf rests on three points, twists under load, and the front edge dips across the 80cm span.

For a paperback bay, the tighter peg pattern gives seven shelves in the space that used to hold six. Repeat that layout across the two bays selected for short-format books. Leave the third bay at the standard 32cm spacing for tall items. The taller bay also breaks up the look of three identical columns, which can make the run feel less like a rigid grid in a living room or study.

Wide shelves still need help under hardbacks

An 80cm BILLY shelf can sag over time when it carries a tight row of heavy hardbacks. In the lower bays that will hold the most weight, slide an 18mm pine batten along the back edge underneath the shelf to reduce the deflection.

Add the height extension and finish the visible edges

The BILLY height extension adds 35cm above the 202cm frame, taking the full run to 237cm. It bolts to the top of the existing bookcase with the supplied cam-lock fittings and uses the same peg system as the main frame. The spacing choices made below can therefore continue in the extension, although the upper shelves are better suited to lighter items.

In a room with 240cm ceilings, the extension nearly closes the gap to the cornice. That removes the dust-collecting void left above an unextended BILLY and gives the run a more built-in profile. Use the extension tier for document boxes, lightweight storage, or overflow that is rarely reached. Keep the heaviest material on the lower three tiers, where the frame and wall fixing are doing the useful work.

The visible finish can stay as supplied, especially if the laminate already matches the room. The other common route is chalk paint, with Annie Sloan and Rust-Oleum as typical choices. Wipe the melamine with methylated spirit first, then paint the front edges and any exposed side panel. A single coat on those visible strips can make a flat-pack run read more like fitted furniture, and the matte surface hides the particleboard edge better than high-gloss paint.

If the same wall is being tiled or papered, deal with the brass curtain pole and any picture rail before the cases are fixed in place. Working around a 2.4 metre run with a drill and tile cutter is awkward, and the frames become unpleasant to move once the shelves are full.

Check the 40% figure against the layout

Start with three 80cm frames at 202cm tall, then add three 35cm height extensions. In the main frames, set two bays for paperbacks at seven tiers each and leave one bay at the standard six tiers for taller books. The extensions add one extra tier above each bay.

The standard arrangement, with no re-pegging and no extension, gives 18 tiers across three frames. The altered arrangement gives 7 plus 7 plus 6 in the main frames, then 3 more in the extensions, for a total of 25 tiers. That is a 39% increase in shelf count, close to the headline figure, because two of the three bays are dedicated to short-format books. If all three bays have to hold a mixed collection, the 22cm gaps will reject too many books and the gain shrinks.

The capacity comes from matching the peg spacing to the book format; pins in every spare hole add little when the books are too tall for the gap.

Melamine keeps a record of changes. Extra holes can be drilled, yet they never disappear as cleanly as the factory peg columns, so the neatest tight layout is also the least forgiving surface to rearrange later.