Chair Upholstery: Welts, Seams and Tufting
Published by Foshanchair · Upholstery workshop in Foshan, China
A buyer approves a fabric swatch, the factory builds the cover, and eighteen months later the seams along the front edge are grinning open. Nothing about the fabric changed. What failed was the construction underneath it — the seam that carried the load, the welt that was meant to protect the edge, the tufting that pulled through the foam. Frame and fabric get all the attention in a specification, and the four decisions in between get none. At Foshanchair we build the same frame with a plain seam or a weltted one, a tight seat or a zip cushion, so the price difference is visible. This guide covers what each detail costs and how to check it on a sample, alongside the restaurant chair range.
1. Four decisions hide inside one cover
Every upholstered seat and back is a set of panels joined four ways, and each one is labour rather than material. The seam type decides where the load sits, the welt decides whether the edge is protected, the tufting decides how the foam is held and how easy the surface is to clean, and the closing method decides whether the cover can ever come off again. Most quotations arrive as one number per chair, so a buyer has no way to see that two suppliers are pricing two different builds. Ask for those four lines separately, even if the answer is a single sentence each. They are the difference between a chair that looks right in the showroom and one that is still in service after five years of lunch service. Everything below sits on frames you can compare in the chair catalogue.
2. What welt cord actually does
A welt, also called piping, is a cord wrapped in the cover fabric and sewn into the seam, normally three to six millimetres in diameter with five millimetres as the contract default. It does two jobs: it hides the raw edge where two panels meet, and it puts a rounded, sacrificial surface exactly where a hand, a bag or a chair back rubs. Without it, that wear lands on a single layer of cloth at the seam line, which is where most upholstery first fails. Cut the welt on the bias so it curves around corners without puckering, and use a firm core — solid foam or vinyl rather than soft paper. A soft core collapses in the first months, the welt flattens and the seam line goes wavy. Run a thumb along a metre of welt on the sample: it should feel like a pencil, not a shoelace. Leisure models with a lot of curved edge are in the leisure chair range.
3. Seams, stitch density and thread
A single row of stitching with no topstitch is the weakest joint a cover can have, because all the load runs through one line of needle holes. A double-stitched seam, with two parallel rows eight to ten millimetres apart, spreads that load across the seam allowance and is what we default to on seat fronts and outside backs. Stitch density should land around seven to nine stitches per inch: too sparse and the loops snag and pull, too dense and the needle perforates PU or coated fabric into a tear line along the seam. Thread should be continuous filament polyester in the Tex 60 to 90 range, UV stabilised, because cotton thread loses strength in humid climates long before the fabric does. On loose-weave fabrics, ask for the seam slippage result as well — an opening of six millimetres or more at 200 N means the yarns will shift and the seam will grin under a guest's weight. Our fabric selection guide covers how to read those numbers against a rub count.
4. Tufting: three methods, three outcomes
Button tufting pulls a twine through the foam and anchors it to the frame. It holds a shape beautifully and it is the version that fails, because every sit flexes the twine and every flex cuts the foam a little further, until the button pulls in or the dimple tears. Each dimple is also a dirt trap in a dining room. Biscuit tufting sews the pattern into the foam in channels, so the look stays and the twine disappears; it is the better contract default. Channel tufting, the vertical fluted back, is a third option: foam wrapped in panels forty to sixty millimetres wide, which reads luxurious, cleans poorly in the valleys between channels, and adds five to fifteen dollars per chair in labour. If a design calls for real buttons, specify them sewn over a biscuit pattern and order a spare button and twine kit. Channel backs are common on the upholstered models in our upholstered restaurant chair builds.
5. Tight seat, loose cushion and how it closes
A tight seat bonds the foam straight to the deck: no zip, no movement, the sharpest look and the lowest cost. It also cannot be rotated, and it compresses first at the front edge, exactly where guests push down to stand. A loose cushion can be turned and later replaced, which usually doubles the usable life of the seat, but only if there is a real deck underneath — webbing or springs under a dust cover, not foam resting on a board. Fill matters too: thirty-five to forty kilograms per cubic metre foam with a twenty to thirty millimetre polyester wrap gives a crown that recovers instead of flattening. The closing decides repairability. A zip, size five or eight, means a cover can be removed for cleaning or replacement; a stapled bottom with a cambric dust cover is neater and cheaper but ends the story the first time a seam goes. Our seat suspension guide covers what should sit under the cushion.
6. What to write on the order and check on the sample
Six lines settle most of this before production starts: seam type and whether it is topstitched, stitch density and thread specification, welt diameter and cord core, tufting method, closing method, and cushion fill with density. Then verify on the sample in ten minutes. Count stitches over one inch with a ruler at the seat front. Pull the seam across its width with both hands and watch for the weave opening. Press each button and each welt corner. Open and close the zip twice. Sit on the cushion for a minute and look for a hollow where the front edge meets the deck. If the sample arrives with a welt that feels soft or a stitch count you cannot see, the production run will be the same, only harder to reject. Our OEM team quotes both a plain-seam and a weltted version of the same model so the upgrade is priced rather than assumed, and the solid wood frames under these covers are in the wooden chair range.
Conclusion
Upholstery fails at the details long before the fabric wears out, and those details are cheap to specify and expensive to discover. Put welt, seam, tufting, closing and fill in writing, then measure them on the sample with a ruler and your hands. Send us the model and the quantity and we will price the two or three constructions that fit the room, so the choice is a number on a quotation instead of a surprise in year two.
Related: Choosing Upholstery Fabric for Chairs · Chair Seat Suspension: Webbing vs Springs
Models we build for this
Factory-direct pricing, custom finish and fabric, MOQ from a few pieces.
