Custom folding chairs are about the gap behind the door
Summary: Custom folding chairs only make sense when the folded size, seat height, and storage spot are known before you order. The chair has to fit the table and the gap where it lives.
We had eleven people for a Sinterklaas dinner two winters ago. Six chairs at the table. Five guests on a mix of stools, a piano bench, and one of those tall office chairs my brother insists on bringing. The food was fine. The seating was a small disaster. By dessert two adults were eating speculaas off their knees on the radiator.
Afterwards I measured the gap behind our front door. 78 cm wide, 4 cm deep when fully open. Five folded chairs would fit there, on a rail, if someone made folding chairs that closed to under 30 mm. Most don't. Standard event-rental folding chairs close to 45 to 55 mm and look like they belong in a parish hall. So you start searching for custom folding chairs and you find a confusing market.
Here's what I learned trying to solve it.
Why off-the-shelf folding chairs almost never fit
The folding-chair industry is built around two customers: event venues and people with caravans. Venues want stackable bulk at the lowest price, so the chair is wide, ugly, and 750 g of bent steel. Caravan buyers want light and weatherproof, so it's aluminium tube and PVC strap. Neither is what you want at a Tuesday dinner.
The everyday-use folding chair is a small, weird category. There's the Plia, designed by Giancarlo Piretti in 1969, still in production. There's a handful of Scandinavian designs in beech and a few Japanese ones in plywood. They cost between 250 and 600 euros each. For four chairs that's already a sofa's worth of money, and they still don't fold to the depth you actually want.
The other thing nobody mentions: folding-chair seat heights are wrong for most modern dining tables. Standard dining tables sit at 73 to 76 cm. Standard dining chairs sit at 45 cm. Folding chairs almost always sit at 43 to 44 cm, because they were designed for taller mid-century tables. Sit on a 43.5 cm chair at a 74.5 cm table and your wrists are pointing slightly upward all evening. By coffee your shoulders know.
What "custom" actually changes
You're not redesigning the mechanism. The hinge geometry on a folding chair is mostly a solved problem and reinventing it ends with pinched fingers. What you can specify is everything around the hinge.
The frame material first. 18 mm birch ply makes a chair that's light, warm, doesn't ring when you set it down on stone, and folds to under 35 mm if the back rail is laminated thin. Solid beech is heavier (about 4.2 kg versus 2.8 kg for ply) but the joinery shows and it ages well. Aluminium is the lightest at around 2 kg but cold to the hand and noisy in a tiled room.
Seat height: pick the actual number. 45 cm if you're matching dining chairs. 46 cm if your table's a hair tall. Don't accept a "standard" answer. The whole point is that the chair fits your table.
Seat depth needs to be 38 to 41 cm for a folding chair that mostly gets used for an hour at a time. Going to 43 cm or beyond starts cutting into the back of the calf when someone leans forward to talk. I tried one 44 cm sample and three different people independently shifted forward to the front edge within ten minutes. Bodies are diagnostic.
Back angle: 5 degrees off vertical for an upright dining chair. 8 to 10 degrees if the chair will get used as a temporary "sit and read" overflow chair in a hallway. More than 10 and it folds badly because the back has to clear the seat.
The folded-depth problem
If you only remember one number from this whole exercise: ask what the chair measures folded. Not the seat. The folded stack.
Most "custom" folding chairs answer this badly because the maker hasn't optimised for it. They've designed a nice chair that happens to fold. You want the inverse: a chair that folds to a specific dimension and happens to seat you.
A well-built ply folding chair can close to 28 to 32 mm. Six of those on a wall-mounted rail behind a door takes up about 19 cm of horizontal depth. Five of them in a 78 cm gap hung vertically on hooks takes up the gap. A mid-range commercial folding chair (45 mm folded) gives you the same total but loses 10 cm of clearance you needed to swing the door open.
Ask for the folded dimension in the quote. If they can't tell you to within 2 mm, they haven't built one yet.
Materials, prices, lead times
A pair of custom folding chairs from a small workshop runs 380 to 700 euros depending on wood and hardware. Solid beech with brass hinges is the top of that range. Birch ply with stainless hinges is the bottom. Six chairs as a set tends to be priced 10 to 15 percent under six individual pairs, which is the sort of arithmetic that makes you order six instead of four.
Lead time is usually six to nine weeks for the small workshops in the Netherlands and Germany I've spoken to. Faster if they have a standard pattern they're willing to resize. The fabric or webbing for the seat (canvas, linen, leather, or just a polished plywood seat with no padding) adds two to three weeks if it's a separate supplier.
The cost of getting the geometry wrong is non-trivial. Two of my friends bought 600-euro folding-chair sets that they now use twice a year because they're slightly the wrong height for their tables. The chairs aren't the problem. The mismatch is.
The boring stuff that decides whether you keep them
Hinges are mostly fine if they're rated for 30,000 cycles. Cheap hinges fail at the rivets within a year of weekly use. Brass and stainless are both fine. Anodised aluminium pivots are quieter than steel.
Glides matter more than people think. Felt glides on hardwood floors. Rubber on tile. Nothing on a wood floor that's already getting a soft patina from older furniture, because rubber leaves marks under load.
The chairs need somewhere to go. A wall hook, a rail, a shelf in the cupboard with a 3.5 cm slot. Decide where they live before you decide what they look like, because if you don't, they'll live leaning against the wall in the kitchen and you'll trip on them in November.
If you've measured the gap behind your front door and counted that you can fit six 30 mm folding chairs there if someone would just build them at 45 cm seat height, that's the kind of geometry knuslabs.com was built around.
If you're planning the same kind of project, start with bespoke furniture design from photos or compare it with AI room design for custom furniture. For adjacent planning detail, read Custom dining chairs, and why six matching ones from a shop almost never work and Planning a corner lounge chair that actually fits your corner.