1Build one ladder
Join two 2200 mm posts with eight 204 mm rungs. Repeat until you have four ladders.
01 · Revised decision
The white bookshelf stays.
The earlier full-wall proposal optimized one number—new shelf metres—and treated relocation as free. That was the wrong priority. The existing 790 mm bookcase already stores books, has no obvious new home and costs nothing to keep.
≈850 kr less
Eight shelf boards instead of eleven, while the existing unit continues working.
≈13.1 m new
Three short bays and eight shelf surfaces, less the switch access slot.
No relocation
No blocked hatch, displaced furniture or speculative second location.
Build from the right edge of the white shelf to the door. The measured opening is 1890 mm. Leave about 15 mm fitting clearance at both ends and make the new frame 1860 mm wide.
02 · Capacity comparison
The new unit equals about 2.8 of the measured wooden bookcases.
Your measured bookcase is 790 mm wide with five shelf levels plus books on top: six usable surfaces. Capacity is compared as linear shelf frontage, because that maps most directly to the number of books.
| Storage | Calculation | Shelf metres |
|---|---|---|
| One measured wooden bookcase | 0.79 × 6 | 4.74 m |
| Two measured bookcases | 0.79 × 6 × 2 | 9.48 m |
| Three measured bookcases | 0.79 × 6 × 3 | 14.22 m |
| New three-bay unit | 0.556 × 3 × 8 − access | ≈13.1 m |
| New unit + retained white shelf | 13.1 + ≈4.7 | ≈17.8 m |
The new construction is 38% larger than two existing wooden units and only about 8% smaller than three. Keeping the white unit gives nearly the same total wall capacity as the expensive full-wall replacement.
03 · Rungs explained visually
First understand one shelf level.
A rung is not a shelf. It is a short 204 mm support rail connecting the front post to the rear post. Two posts plus eight rungs make one ladder-shaped side frame. Four of these ladder frames stand upright across the width of the bookcase. The long shelf boards lie left-to-right on top of matching rungs.
Vertical postShort rung under shelfLong shelf boardDownward screwBrace
The simplest mental picture: build four narrow wooden ladders, stand them parallel like four bookends, then lay shelf boards across corresponding ladder rungs. The rungs are the ledges carrying the shelf boards.
1. End/side view
You are standing at the end of the bookcase and looking along its width.
SIDE VIEWSHELF RESTS ON RUNG
What you see: one front post, one rear post and the short rungs between them.
2. Front view
You are facing the books. Only the front post of each ladder is obvious.
FRONT VIEWSHELF BOARDS RUN LEFT ↔ RIGHT
What you see: four support stations and one continuous-looking shelf level.
3. View from above
You are looking down before books are loaded. The wall is at the top.
TOP VIEWWALL / REAR POSTSROOM / FRONT POSTS
What you see: the 200 mm-deep shelf fits inside the 204 mm gap between rear and front posts.
One shelf level, in six pictures
2Stand four ladders
Stand them parallel. Matching rungs must have exactly the same top height and be level.
3Lower three boards
↓
Place 628 + 604 + 628 mm across the rungs. Together they make one 1860 mm shelf level.
4Centre and clamp
CLAMP FLUSH
Each joint must sit on the middle of a shared 48 mm rung: 24 mm supports the board on each side.
5Drill downward
Drill a clearance hole through the shelf and a smaller pilot hole into the rung below.
6Drive the screw
Drive a 4 × 50 screw from the shelf top into the rung. Stop when the head is flush.
Nothing is floating. The shelf sits physically on the rung. The rung is screwed to both posts. The downward shelf screws prevent sliding and make the whole frame rigid; they are not carrying the book load by themselves.
04 · Room and dimensions
Three 556 mm bays in the measured opening.
Front elevation · existing shelf plus new three-bay frame
556556556
1860 new unit · about 15 mm fitting gap each side
Ladder-frame left edges: 0, 604, 1208 and 1812 mm measured from the new unit’s left edge. Four 48 mm stations plus three 556 mm clear bays = 1860 mm.
Plan view · distinguish shelf depth from frame depth
BLUE WALL + SURFACE ELECTRICAL SERVICES
50 mm clear service chase
200 mm shelf fits in a 204 mm opening between front and rear
posts
50 gap300 frame: 48 post + 204 opening + 48 post350 mm total projection from wall
The boards are 200 mm deep; the outside of the paired-post frame is 300 mm deep. The extra 4 mm inside the posts gives 2 mm fitting clearance at the front and rear of every shelf.
| Element | Size / position | Reason |
|---|---|---|
| Measured opening | 1890 mm | 1340 to switch + 50 switch + 500 to door |
| Finished new unit | 1860 × 2200 mm | About 15 mm fitting tolerance each end; 100 mm below ceiling |
| Clear bay | 556 mm | Short, stiff span for continuously loaded 18 mm pine |
| Rung-top heights | 70 / 390 / 700 / 990 / 1280 / 1570 / 1860 / 2020 | Eight shelf surfaces; shelf tops are 18 mm higher |
| Normal clear rows | 272–302 mm | Fits the dominant books visible in the room |
| Compact top row | 142 mm | Horizontal stacks and small books |
05 · Materials and exact cuts
Eight shelf boards; six lengths of framing wood.
| Material | Qty | Reference price | Subtotal | Use |
|---|---|---|---|---|
| 18 × 200 × 2000 mm gran/furu shelf board | 8 | 249 kr | 1,992 kr | 24 shelf pieces: one stock board per complete level |
| 48 × 48 × 4800 mm untreated class-1 lekt | 6 | 103 kr | 618 kr | 8 posts + 32 depth rungs |
| 9–18 mm plywood/OSB offcut + perforated strap | 4 panels + rear X | allow 250–500 | 250–500 | Side-frame shear panels and width-direction bracing |
| 5 × 100 TX25 partial-thread structural wood screws | 200 | allow 300–450 | 300–450 | 128 used at rung-to-post joints |
| 4 × 50 TX20 screws | 200 | allow 200–300 | 200–300 | Shelves and shear panels; strap screws must match the strap holes |
| D3 glue + wall-restraint hardware | — | allow 250–450 | 250–450 | Side ladders and mandatory anti-tip anchoring |
| Estimated structural total | ≈3,600–4,300 kr | Finish optional; use a cheap panel offcut if available |
Each 2000 mm shelf board makes one whole shelf level
At every height, install 628 + 604 + 628 mm. The two joints land on the centres of the shared 48 mm rungs. Confirm the finished 1860 mm width before cutting all eight boards.
| Part | Qty | Cut length | Label / note |
|---|---|---|---|
| Posts | 8 | 2200 mm | L1-front/rear through L4-front/rear |
| Depth rungs | 32 | 204 mm | Eight per ladder; outside frame depth becomes exactly 300 mm |
| Outer shelf pieces | 16 | 628 mm | Left and right piece at each level |
| Middle shelf pieces | 8 | 604 mm | One per level |
| Side shear panels | 4 | 300 × 200 mm | 9–18 mm plywood/OSB; two on each outer ladder |
| Rear X straps | 2 | Measure after squaring | Galvanised perforated strap with compatible pan-head/washered screws |
| Wall spacer blocks | At least 3 | 50 mm deep | Fit only at verified structural anchor locations |
Stock plan for the 48 × 48: four lengths each produce two 2200 mm posts and one 204 mm rung from the remainder. A fifth length produces about 23 rungs; the sixth produces the last five and leaves useful jig/spacer stock. Kerf and imperfect ends are why five lengths are not enough.
06 · Structural system
Three different parts resist three different movements.
| Possible movement | Part that stops it | Connection |
|---|---|---|
| Shelf bends downward under books | 556 mm clear span + 18 mm solid pine | Each end bears on a 48 mm rung |
| Front posts lean relative to rear posts | Top and bottom shear panels on both outside ladders | Glue + six screws per panel |
| Whole unit leans left or right | Two rear straps forming an X | Strap screwed to all four rear posts |
| Whole unit tips into the room | At least three independent wall restraints | Verified stud/masonry anchors with rigid 50 mm spacers |
Load path: books → 18 mm shelf board → 204 mm rung at each end → paired 48 × 48 posts → floor. The screws stop parts sliding and racking; the shelf load itself is carried by wood bearing on wood, not by a screw hanging in empty space.
07 · How the two posts on each side are braced
Build four ladders; stiffen both outside ladders with shear panels.
Side elevation of one outside ladder
300 × 200 SHEAR PANEL
outside face
outside face
300 × 200 SHEAR PANEL
outside face
outside face
300 outside · 204 clear between posts
Rung-to-post jointPut the rung between the
posts with its top exactly on the story-stick mark. Clamp
the joint. Pilot through the post and drive
2 × 5×100 into each rung end using the
staggered drilling template in the next section. Glue is
optional and is not counted as structural support at this
end-grain joint.
Shear-panel fixingGlue one 300 × 200 panel
across the outside faces of both posts at the bottom and
another at the top. Use
3 × 4×50 screws into
each post: six per panel. Put the screw line through the 24
mm centre of each post.
Repeat on the other endThe far-left and
far-right ladders each receive two panels. The two middle
shared ladders do not need panels; the fixed shelves tie
them to the braced ends.
A panel is more beginner-proof than a shallow diagonal on a 300 mm-wide frame: it creates a rigid shear plate and cannot loosen because its angle was cut imperfectly.
- Cut two posts and eight identical 204 mm rungs for each ladder.
- Make one story stick with rung-top heights 70, 390, 700, 990, 1280, 1570, 1860 and 2020 mm.
- Lay the two posts on a flat surface, exactly 204 mm apart. Clamp temporary blocks outside them so nothing moves.
- Install the bottom and top rungs first. Check the two frame diagonals; they must match before installing the other six.
- Install the remaining rungs with the same two-screw pattern. Wipe away squeezed-out glue if you chose to use it.
- On ladder L1 and ladder L4 only, glue and screw the top and bottom shear panels to the outward-facing side.
If cheap panel offcuts are unavailable: use two perforated straps forming a complete X on the outside face of each end ladder. One strap alone works well in only one tension direction; the pair is required. Do not omit side bracing and assume the rear X performs the same job—it braces a different plane.
08 · Drill the rung-to-post joint
Two staggered screws through each post into each rung end.
The final specification is a partially threaded 5 × 100 mm structural wood screw. It travels through the 48 mm post and approximately 52 mm into the 204 mm rung. Each rung has two ends, and each end receives two screws: four screws per rung.
Why 100 mm? A typical 5 × 100 ESSDRIVE screw has approximately 53 mm of thread and 47 mm of unthreaded shank. That closely matches the 48 mm post: the shank passes through the post while the thread grips the rung. The screw cannot reach the far post because the rung alone is 204 mm long.
Diagram A · marks on the outside post face
You are looking straight at the 48 × 48 mm outside face of one post. The rung end is hidden immediately behind this square.
AB
16 mm
16 mm
15 mm down
15 mm up
Hole A: 16 mm from the left edge and 15 mm below the rung top. Hole B: 16 mm from the right edge and 15 mm above the rung bottom—equivalently 33 mm below its top. The diagonal stagger avoids creating one straight split line.
Diagram B · horizontal cutaway through one screw
Imagine slicing through the joint along the screw. The outside of the post is at left; the screw travels toward the rung.
48 mm POST
204 mm RUNG
Screw axis must remain square in both directions
≈47–48 mm shank
≈52–53 mm thread in rung
The thread belongs in the rung, not mostly in the post. Buy partially threaded structural wood screws and check the actual thread length printed by the manufacturer.
Diagram C · drilling order for every pair of holes
1 · Clamp first
Clamp the rung tightly between the two posts. Its top must match the story-stick line and its end must touch the post.
2 · Clearance through post
At A and B, drill a 4 mm clearance hole through only the 48 mm post. Use tape on the bit at approximately 48 mm.
3 · Pilot into rung
Through the clearance hole, drill a 3 mm pilot to approximately 90 mm total depth from the outside face.
4 · Drive and stop flush
Lightly countersink, then drive the 5 × 100 screw in low gear. Stop when the head is flush—do not bury it.
Full procedure for one rung
- Draw the rung-top line across both posts with a try square. Draw a second line 48 mm below it so the hidden rung end is visible as a pencilled square on the outside face.
- Put the 204 mm rung between the posts. Clamp the complete ladder against square stops so the gap stays 204 mm.
- Mark A at 16 mm from the left and 15 mm below the top line. Mark B at 16 mm from the right and 15 mm above the bottom line. Prick both centres with an awl.
- Hold a small square beside the drill bit. Drill A perpendicular to the post face. Check from above as well as from the side; a drill can look square in one view while wandering in the other.
- Make the 4 mm clearance hole through the post, then change to a 3 mm long bit and pilot to about 90 mm total depth. Repeat at B.
- If using D3 glue, apply only a thin film to the mating end. Do not treat end-grain glue as a substitute for screws, bracing or accurate drilling.
- Insert both screws. Drive A halfway, then B halfway. Alternate until both heads are flush; this pulls the rung in evenly instead of twisting it toward the first screw.
- Repeat on the other post at the far end of the same rung. The opposite pair enters from the opposite outside face and cannot meet the first pair inside a 204 mm rung.
- Remove the clamps and push the rung down, up and sideways. Reject and remake the joint if the wood splits, a screw spins without tightening, or the rung moves.
Practise once on offcuts.
Join a 204 mm scrap between two short post scraps before drilling a real ladder. Saw the practice joint apart afterward if you want to see where the pilots and screws actually went.
Do not drill through knots or cracks.
Move the rung slightly or choose another post. Use structural wood screws, not brittle drywall/plasterboard screws, and do not use the finished shelf as a climbing ladder.
Technical references: ESSVE 5 × 100 specification, ESSVE load-capacity assumptions. This is a furniture-joint drilling layout, not an engineering certification for climbing or occupancy loads.
09 · How the shelves connect to the posts
The shelves screw downward into rungs—not sideways into shelf end grain.
Every shelf board sits between the front and rear posts with about 2 mm clearance at both edges. The rung is directly beneath the entire 200 mm depth of the shelf end. The rung then transfers the weight into the front and rear posts.
View from directly above · one shared middle ladder
BOARD JOINT
24 mm24 mm
Left shelf board ends at the dashed centre line. Its two black screw heads are 12 mm left of the joint.
Right shelf board starts at the joint. Its two screw heads are 12 mm right of the joint.
The brown strip underneath is one 48 mm-wide rung running rear-to-front. Half of it supports the left board; half supports the right board. The pine blocks beyond the board are the rear and front posts.
Cutaway through one screw · what is underneath what
18 mm shelf
≈32 mm into rung
The board rests on the rung before the screw is fitted. The 50 mm screw passes through 18 mm of shelf and embeds about 32 mm into the 48 mm-high rung.
Install one complete shelf level—slowly, the first time
- Confirm the four landing pads. Put a long straightedge across the four rungs at this height. It must touch all four without rocking. Correct shims or ladder position before adding a board.
- Place the left board. Put one 628 mm piece from the outside edge of ladder L1 to the centre of ladder L2. Do not screw yet.
- Place the middle board. Put the 604 mm piece from the centre of L2 to the centre of L3. Its left cut edge meets the first board over L2.
- Place the right board. Put the second 628 mm piece from the centre of L3 to the outside edge of L4.
- Set the depth. Use two temporary 2 mm spacers so the 200 mm boards sit centrally in the 204 mm opening between rear and front posts. Remove the spacers after fixing.
- Clamp both shared joints flush. The seams must be on the exact centre line of the L2 and L3 rungs. Each board gets 24 mm of support. Clamp across each seam so one board cannot sit higher than the other.
- Mark the outer ends. On L1 and L4, mark two holes per board end: 24 mm from the outer cut edge, one 45 mm from the rear edge and one 45 mm from the front edge.
- Mark each shared joint. On both sides of each seam, mark holes 12 mm from the seam and 45 mm from the rear/front edges. That makes four holes around each shared rung: rear-left, rear-right, front-left and front-right.
- Drill in two stages. Drill a 4 mm clearance hole through the 18 mm shelf only. Then use a smaller 2.5–3 mm bit through that hole to pilot approximately 35 mm into the rung. Keep the drill vertical.
- Countersink lightly. Make only enough recess for the screw head to finish flush. Do not create a deep crater in soft pine.
- Drive twelve 4 × 50 screws. Four secure the left piece, four the middle and four the right. Stop each screw when its head is flush with the shelf.
- Remove clamps and test. Press at every joint and corner. Nothing should click, rock or lift. Recheck that the ladders remain plumb before installing the next shelf level.
Screw count for one level: L1 outer rung = 2; shared L2 rung = 4; shared L3 rung = 4; L4 outer rung = 2. Total = 12 downward screws.
Do not drive a long screw horizontally through a post into the shelf’s end grain. End-grain withdrawal strength is poor and that connection asks the screws to carry the books. Downward screws into the support rungs keep the load in wood-to-wood bearing and make every fixed shelf help square the frame.
10 · Rear X and wall restraint
Square it, brace it, then anchor it.
Rear elevation · width-direction brace
TWO STRAPS = X3+ WALL RESTRAINTS AT TOP
The rear X prevents the 1860 mm-wide unit becoming a parallelogram. The side panels prevent the 300 mm-deep end frames becoming parallelograms. Both are necessary.
- With bottom, middle and top shelf levels fixed, measure the full rear diagonal from bottom-left to top-right.
- Measure bottom-right to top-left. Push the frame gently until the two dimensions are equal.
- Pull the first perforated strap tight from bottom-left to top-right. Fix it to every rear post it crosses using screws whose head and diameter suit the strap holes—normally pan-head or washered screws, not countersunk drywall screws.
- Install the second strap from bottom-right to top-left, again tight and fixed at every rear post.
- Recheck the diagonals. A difference means the frame moved; loosen, square and retighten.
- Install at least three independent top restraints through rigid 50 mm spacer blocks into verified studs or masonry. Use the two outer rear posts and at least one middle rear post.
Wall restraint is mandatory. A 2.2 m frame full of books is a severe crush hazard. Plasterboard alone is not a structural anchor. Visible surface conduit and electrical boxes make exploratory drilling unsafe: establish the wall construction and safe anchor lines first.
11 · Switch and electrical access
One shelf passes below the switch and the next passes above it.
The switch occupies 1070–1130 mm above the floor. The shelf below has its top at 1008 mm; the next shelf begins at 1280 mm. This leaves a 272 mm-high access row.
- After positioning the frame, transfer the actual switch centre onto the 1008 mm shelf. It should be roughly 1350 mm from the new unit’s left edge, but the wall measurement wins.
- Fix two small book-stop blocks about 150 mm apart, centred on the switch. Keep that strip free of books.
- Reach through the open back to use the switch. The 50 mm service chase keeps the frame clear of the surface conduit.
- Measure the high electrical box separately. Keep a second access slot in the top row and never place a wall anchor near its wiring route.
12 · Complete build sequence
Build the ladders flat; assemble the width in the room.
- Verify dimensions. Measure the 1890 mm opening at floor, switch and top height; ceiling at four ladder positions; switch and upper-box X/Y; skirting; door trim; and safe wall-anchor locations.
- Buy and acclimatise straight stock. Reject twisted posts, pith and severe bow. Use untreated indoor framing timber, not green pressure-treated stock.
- Make the story stick. Mark the eight rung-top heights once and transfer them to all eight posts from the floor end.
- Cut the frame. Cut eight 2200 mm posts and thirty-two 204 mm rungs. Label each ladder before assembly.
- Build four ladder frames. Glue, pilot and install two 5 × 100 screws at every rung end. Square each ladder before the glue sets.
- Brace the outer ladders. Add top and bottom 300 × 200 shear panels to the exterior face of L1 and L4.
- Cut shelf boards. From each 2000 mm board cut 628, 604 and 628 mm. Label all pieces by shelf level and position.
- Stand and space the ladders. Leave about 15 mm beside the old shelf. Place the ladders at 0, 604, 1208 and 1812 mm; shim their feet until corresponding rungs are level.
- Lock the geometry. Install the bottom, middle and top shelf levels first using downward 4 × 50 screws. Check the overall rear diagonals.
- Add the remaining five levels. Keep every joint centred and every surface flush. Add switch/outlet book stops while access is easy.
- Install the rear X. Square first, tension both straps, and fix each strap to every rear post it crosses.
- Anchor to the wall. Use at least three verified structural points and rigid 50 mm spacers. Do not load books before this is complete.
- Load bottom-up. Put the heaviest books low. Watch every joint and restraint during the first loading; stop if anything moves.
13 · Reduce the cost right now
Build the complete frame, but add shelves in stages if needed.
| Phase | Buy / install | Approximate spend | Result |
|---|---|---|---|
| Phase 1 | All posts, rungs, bracing, anchors and five shelf boards | ≈2,850–3,550 kr | Complete safe structure with five new shelf surfaces |
| Phase 2 | Three more 18 × 200 × 2000 boards | ≈747 kr | Add the final three shelf levels later |
The bottom, a middle level and the top level must be fixed in Phase 1, together with both side braces, the rear X and all wall restraints. Do not postpone structural bracing.
Why not six posts? Two bays in the same 1860 mm width would have approximately 858 mm clear spans. That saves only about one 103 kr framing length but would need thicker shelves or front stiffeners. Eight posts are the cheaper durable system.
Full-wall version remains an optional future rebuild
If the white shelf eventually finds a useful home elsewhere, the 2640 mm four-bay design can still be built. It is not the current recommendation: it costs more, requires moving functioning furniture and adds only about one shelf metre compared with the retained-shelf combination.
Before buying one board
Confirm these measurements.
- Opening from white shelf to door at three heights
- Ceiling height at four ladder positions
- Exact switch X/Y from the new unit’s left edge
- Exact upper electrical-box X/Y and projection
- Skirting-board height and projection
- Door-casing and door-swing clearance
- At least three safe structural anchor locations
- A representative ordinary book fits a 200 mm-deep board
The design target is 1860 × 2200 mm. If the narrowest measured opening is less than 1890 mm, reduce the finished width and recalculate the three equal bays before cutting shelves.