Upholstery
Upholstery builds a padded surface from suspension, foam, wadding and textile over a frame, fixed with staples, ties and stitching.
- Part
- Joining
- Revised
- 2026-08-11
At a glance
- Family
- Mechanical
- Typical volumes
- 1 to 100,000+ — hand work for one-offs and restoration, CNC cutting and sewing cells for production runs
- Lead time
- Hours of hand labor per seat for traditional sprung upholstery; production cut-and-sew cells work in minutes per panel once patterns and cutting nests exist
- Materials
- Composite
What it is
Upholstery builds a padded seating surface in layers over a frame: suspension, foundation, foam, wadding, cover and trim, fixed with staples, ties and stitching. Each layer does a distinct job, and the failure modes of a seat almost always trace back to one of them being specified for appearance rather than function.
The two numbers that define a cushion are foam density and IFD. Seat foam is typically 1.8–2.8 lb/ft³ (29–45 kg/m³) with an indentation force deflection of roughly 25–50 lbf at 25% deflection; density predicts how long the foam lasts, IFD predicts how firm it feels, and they are independent.
Cover fabric is specified by abrasion resistance — 15,000 double rubs on the Wyzenbeek test or 20,000 Martindale cycles is the usual minimum for contract upholstery, with heavy-duty commercial fabrics rated far higher. Flammability is governed by regulation, not preference: California TB 117-2013 in the US, TB 133 for public occupancy seating.
How it works
- Frame. Kiln-dried hardwood at 7–9% moisture content, or steel or molded plastic in production furniture. Corner blocks are glued and screwed, not just nailed — a racking frame destroys everything built on top of it.
- Suspension. Interwoven jute webbing roughly 3-1/2 in (90 mm) wide stretched with a web stretcher, sinuous ("no-sag") springs at about 4–5 in (100–125 mm) centers with a crown of about 1 in per foot of span, or coil springs hand-tied eight ways in traditional work. This layer, not the foam, determines how the seat feels over years of use.
- Foundation. Burlap or a decking fabric over the suspension to stop the padding from being pushed down between the springs or webbing.
- Padding. Polyurethane foam cut to shape, often with a firmer core and softer topper, wrapped in polyester wadding to soften the edges and stop the cover from abrading directly against the foam.
- Cover. Panels are cut — allowing extra yardage for pattern matching — sewn with bonded nylon or polyester thread at roughly 6–8 stitches per inch, then pulled over the padding and fixed with fine-wire staples at 1–1-1/2 in (25–38 mm) spacing into the frame.
- Trim and finish. Welt, piping, buttoning, gimp or a dust cover closes out the visible edges.
Cut-and-sew is the production version of the same sequence: CNC fabric cutting from nested patterns, sewing cells, and foam pouring or cutting to a fixed profile, with the assembly still done by hand.
Design guidelines
Specify foam by density and IFD separately
Density (lb/ft³ or kg/m³) predicts durability — how many cycles the foam survives before it loses height. IFD (lbf at 25% deflection) predicts firmness. They are independent properties, and specifying only "firm foam" produces a cushion that feels right in the showroom and collapses in eighteen months. Seat cushions typically use 1.8–2.8 lb/ft³ (29–45 kg/m³) at 25–50 lbf IFD; back cushions use lower values of both.
Match fabric abrasion rating to use
Specify by test result, not by appearance. Roughly 15,000 Wyzenbeek double rubs or 20,000 Martindale cycles is the accepted minimum for general contract upholstery; residential light-use fabrics sit below that and heavy commercial fabrics well above. Loose weaves and long floats also snag regardless of their abrasion number, which the test does not capture.
Design the suspension for the load path
The suspension carries the load; the foam only distributes it. Sinuous springs at 4–5 in (100–125 mm) centers with a crown of about 1 in per foot of span, or properly stretched webbing, are what keep a seat from bottoming out. Adding foam to fix a sagging seat treats the symptom.
Allow for the cover
Cut-and-sew consumes more material than the finished area suggests: a 1/2 in (13 mm) seam allowance on every seam, plus 15–30% extra yardage where a pattern must be matched across panels, plus enough pull-in at the staple line to tension the cover.
Verify against the regulation that applies
Flammability requirements are jurisdictional and non-negotiable: California TB 117-2013 covers smolder resistance of cover fabrics and barrier materials in the US, TB 133 applies to public-occupancy seating, and the UK Furniture and Furnishings (Fire) (Safety) Regulations govern in Britain. Confirm which one applies before specifying either fabric or foam, since a compliant construction usually depends on a barrier layer as well as the cover.
Inspection
Seam strength and stitch quality on samples, foam density and IFD verified against the supplier's certification, and cushion fatigue testing to ASTM D3574 constant-force pounding for foam durability. For commercial and institutional seating, BIFMA X5.4 covers lounge and public seating with a defined sequence of drop, cyclic load and stability tests, and EN 1728 is the European equivalent. Visual inspection covers seam alignment, pattern match, cover tension and staple spacing.
Cost drivers
Upholstery is labor-dominated at every volume. Traditional hand upholstery over a sprung frame takes hours per seat and cannot be meaningfully mechanized; even in production cut-and-sew, the assembly step remains hand work. That is why upholstered furniture costs what it does.
Material cost is dominated by cover fabric, and it is driven as much by yield as by price per yard. A patterned fabric that must be matched across panels can consume 15–30% more than a plain one for the same seat, and railroaded versus up-the-roll orientation changes the nest entirely.
Foam and suspension are comparatively inexpensive and are exactly where specification cuts get made — usually to the long-term detriment of the product, since foam density and spring quality determine how the piece performs after a few years rather than on delivery day.
- Design panels to nest. Pattern layout that yields well from a standard roll width is worth more than a small discount on the fabric.
- Specify plain or non-directional fabrics where the design permits and recover the 15–30% pattern-matching allowance.
- Make cushions removable and re-coverable. Serviceability extends product life and turns a failure into a repair.
- Standardize foam profiles across a range so cutting or molding is shared between models.
- Do not economize on suspension or foam density. Both are small parts of the bill of materials and large parts of how the product is judged after two years.
Questions
5 questionsHow do I specify upholstery foam?
By density and IFD separately. Density — typically 1.8–2.8 lb/ft³ (29–45 kg/m³) for seat cushions — predicts how long the foam holds its height. IFD, roughly 25–50 lbf at 25% deflection for seating, predicts how firm it feels. They are independent, so specifying only firmness gives a cushion that feels correct at delivery and collapses within a couple of years.
What abrasion rating does upholstery fabric need?
Around 15,000 double rubs on the Wyzenbeek test or 20,000 cycles on Martindale is the accepted minimum for general contract upholstery, with heavy commercial fabrics rated substantially higher and residential light-duty fabrics below. Note that abrasion testing does not capture snagging, so loose weaves and long floats can fail in service despite a good rating.
Why does a seat sag even with good foam?
Because the suspension carries the load and the foam only distributes it. Stretched webbing, sinuous springs at 4–5 in (100–125 mm) centers with about 1 in of crown per foot of span, or hand-tied coils are what stop a seat bottoming out. Adding or upgrading foam to correct a sagging seat treats the symptom rather than the cause.
How much extra fabric does pattern matching cost?
Typically 15–30% more yardage than an unmatched plain fabric for the same piece, because panels must be cut on repeat rather than nested for yield. Seam allowances of about 1/2 in (13 mm) and the pull-in needed to tension the cover at the staple line add further to the difference between finished area and purchased yardage.
Which flammability standard applies to upholstered furniture?
It depends on jurisdiction and use. In the US, California TB 117-2013 covers smolder resistance of cover fabric and barrier materials and is widely adopted, while TB 133 applies to public-occupancy seating. In the UK the Furniture and Furnishings (Fire) (Safety) Regulations apply. Compliance is usually achieved by a combination of cover and barrier layer, so confirm the requirement before specifying either.