Practical · 4 min read
Assembling a Piece That Ships Flat
Fewer fasteners and tighter tolerances than flat-pack. How to assemble a flat-shipped piece so it sits square and stays tight.
A flat-shipped piece from a workshop is not flat-pack. There are fewer parts, the tolerances are tighter, and there is usually no fitting that compensates for being slightly off. That makes it quicker to assemble and less forgiving of doing it in the wrong order.
Set up first
- A flat floor, which is the reference surface for everything. A piece assembled on a sloping or uneven floor comes out twisted.
- A blanket or cardboard underneath, because the new finish is at its most vulnerable and the floor is at risk too.
- Lay all the parts out and count them against the list before starting.
- Use the supplied tool if there is one. The Side Shelf assembles with one key, sized for its fixings. A power driver in the same holes is how threads get stripped.
- Read it through once. Two minutes, and it is where you discover that part C goes on before part B.
The order that matters
- Assemble everything loosely. Every fixing engaged, nothing tight. The piece should be floppy and complete.
- Square it up. On a flat floor, press it into square and check that it sits on all its feet without rocking. Measure the diagonals on anything rectangular: equal diagonals mean square.
- Tighten in sequence, going round rather than finishing one joint at a time. Work from the middle outwards where there is a middle.
- Snug, not brutal. Overtightening strips threads in timber and distorts thin steel, and both of those cause the looseness you were trying to prevent.
- Check it again on the floor before moving it to its final position.
Tightening one fixing fully before the others is the single most common assembly error. It pulls the piece into a shape and every subsequent fixing locks that shape in.
Things that go wrong
A fixing that spins without biting. Stop immediately. The hole is damaged and forcing it makes the repair worse. Ask before continuing.
A part that will not line up. Nine times out of ten something earlier is in the wrong orientation. Look for the orientation mark rather than applying force. Workshop pieces are made to fit and are not meant to need persuasion.
A piece that rocks when assembled. Check whether it is the furniture or the floor by turning it ninety degrees. If the rock follows the piece, it is out of square and wants loosening and resquaring. If it stays with the spot, it is the floor, and levelling on an uneven floor covers the fix.
Marks on the finish from the assembly. This is the argument for the blanket. A new finish is not fully cured and marks easily.
Hanging, where that is an option
Some flat-shipped pieces can be hung instead of standing. The Side Shelf hangs from two screws, and 9.4 kg plus whatever goes on it is well within what an ordinary wall takes with the right fixing.
The wall decides the fixing, not the shelf. Solid masonry, plasterboard with a stud behind, plasterboard with nothing behind: three different answers, and the third one needs a proper cavity fixing rather than an optimistic plug. Find the studs rather than guessing, and get both fixings level, because the second one is what stops it rotating. Shelf load capacity covers what the loaded shelf is actually asking of the wall.
After assembly
- Pads on the feet before moving it to its position, not after. Felt pads and floor protection.
- Lift it into place. Dragging an assembled piece puts side load through joints that have just been tightened.
- Retighten after a fortnight. Everything settles, and the first check is the one that matters.
- Then annually. Bolted joints lose clamping force slowly, and a joint that has started to move wears its own hole. Welded versus bolted explains the mechanism.
- Keep the key somewhere you will find it. Tape it inside the piece if there is anywhere discreet.
Reality check
- Assemble loose, square it, then tighten in sequence.
- Flat floor, blanket underneath, supplied tool, no power driver.
- A spinning fixing means stop, not push harder.
- Rock that follows the piece is square; rock that stays put is the floor.
- Retighten at a fortnight and then once a year.
Common questions
- Why does assembly order matter?
- Tightening one fixing fully before the others pulls the piece out of square and locks the error in. Snug everything first, square it, then tighten.
- Should I assemble on the floor or in place?
- On a flat floor, on a blanket, then move it. Assembling against a wall usually means building it out of square.
- What if a fixing will not bite?
- Stop. A spinning fixing means the hole is damaged, and forcing it makes the repair harder. Ask before continuing.
- Do I need to retighten later?
- Yes. Check once after a fortnight and then annually. Five minutes prevents the only failure mode a bolted piece has.