Spacer Fabric: Structure, Properties and the Machine That Knits It

October 28, 2026

Spacer fabric is a three-dimensional warp knit made of two separate face layers held apart by a layer of monofilament pile yarns. It is knitted in one pass on a double needle bar Raschel machine, and the gap between the two faces is what gives it cushioning, airflow and compression recovery without any foam or lamination.

Most buyers meet spacer fabric as a finished roll: a mattress ticking, a shoe upper, a seat insert. This page works backwards from that roll to the machine, so that a mill considering a double needle bar line knows which decisions on the machine side fix the thickness, the hand and the recovery of the fabric it will sell.

What a spacer fabric is made of

The structure has three layers. A top face, a bottom face and a middle layer of connecting yarns that run between them. The face yarns are usually multifilament and the connecting yarns are monofilament, which is why the middle layer stands up instead of collapsing like a plush pile.

Typical overall thickness runs from about 1 mm to 15 mm, with each face around 0.4 mm to 1 mm thick. The common commercial range is 6 mm to 8 mm. One commercial sample measured in a finite element study used polyester monofilament of 0.2 mm diameter as the connecting yarn and came out at 7.52 mm total thickness.

There is no standard monofilament diameter. Patents for special uses go much finer: a membrane filtration spacer used paired 60 μm monofilaments or single 100 μm to 150 μm threads to keep compression low, and a tissue engineering support used 220 dtex polylactic acid monofilament at roughly 150 μm. The diameter is a design choice tied to the thickness you want and the load the fabric must push back against.

How the double needle bar machine builds it

A double needle bar Raschel carries two rows of needles facing each other. The outer guide bars lap on the front needle bar only and the inner ones on the back bar only, so each bar set knits its own face. The guide bars carrying the spacer monofilament lap across both needle bars in turn, tying the two faces together with a pile yarn that stands at the distance set between the bars. A six guide bar arrangement is the configuration described in the reference literature for this job.

Three machine-side settings decide what comes off the machine:

• Distance between the needle bars. This sets the gap the monofilament has to bridge, and therefore the fabric thickness. A line sold for thick cushioning fabric has a wider adjustable range than a standard double Raschel, which is why our high distance spacer machine is listed separately from the general spacer fabric machine.
• Monofilament diameter and material. Thicker and stiffer monofilament gives firmer support and faster recovery after compression. Finer monofilament gives a softer fabric that compresses more easily. The same machine knits both, but the yarn path, tensioners and needle hooks must suit the stiffness you choose.
• Face construction. Open mesh faces give the airflow that mattress and seat buyers pay for. Closed faces give a smoother surface for lamination or printing. Face openness comes from the lapping of the face bars, not from the spacer bars.

If you are new to the two bar system, read how a double Raschel machine works first, then the double needle bar machine guide for the bar and gauge terms used below.

Where it is used and why foam loses

The reference sources list body protection, mattresses, sportswear, car interiors and seats, shoe soles, bra cups and knee and elbow protectors as the main applications. The common thread is that each of these once used laminated foam.

Spacer fabric wins in those jobs for reasons that come directly from its structure: it is light, it lets air through, it holds less moisture than foam or rubber, and the monofilament pile springs back after compression. It is also made from a single fiber type, so a worn mattress panel or a seat insert can go into one recycling stream instead of being separated from a glued foam core.

Our shoe spacer fabric application page covers the footwear side, and the jacquard shoes spacer machine adds patterning on the face for uppers that need a visible design as well as cushioning.

Spacer fabric compared with other knitted constructions

Plush is the construction most often confused with spacer fabric because both start on a double needle bar machine. The difference is the last step: plush is slit through the middle to make two pile fabrics, while spacer fabric is left whole so the connecting yarns keep working as springs. For the single bar side of the comparison, see our page on Raschel knit fabric.

Conditional conclusions for a mill choosing a line

• If your product needs a fabric thicker than the common 6 mm to 8 mm band, specify a machine whose needle bar distance range covers your target, and budget for stiffer monofilament. A standard double Raschel will not reach the top of the 15 mm range.
• If your buyers are mattress or seat makers, prioritise open mesh face constructions and a monofilament stiff enough to recover under sustained load. Softness is secondary in these markets.
• If your buyers are shoe upper makers, patterning on the face matters as much as cushioning, which points to a jacquard capable spacer machine rather than a plain one.
• If your target fabric is under about 1 mm thick, a spacer construction is the wrong tool. That range belongs to flat tricot or single bar Raschel fabrics.

These conclusions do not apply to woven or weft knitted spacer constructions, which are made on different machinery and follow different thickness limits. They also do not cover medical or filtration spacer grades, where the monofilament is far finer than the textile range discussed here.

Before placing an order for any double needle bar line, send us a sample of the spacer fabric you intend to make or a target thickness and end use, and we will map it to a needle bar distance and bar configuration. Our product range is listed on grandstarcn.com, and the fastest route to a technical answer is the contact page on this site.

Frequently Asked Questions

What is spacer fabric made of?

Two knitted face layers, usually multifilament yarn, joined by a middle layer of monofilament pile that holds them apart. The three layers are knitted together in one pass on a double needle bar Raschel machine.

How thick can spacer fabric be?

The typical range is about 1 mm to 15 mm overall, with each face around 0.4 mm to 1 mm. Most commercial grades sit between 6 mm and 8 mm. Thickness is set by the distance between the two needle bars on the machine.

Why is spacer fabric used instead of foam?

It is lighter, lets air through, holds less moisture and springs back after compression because the monofilament pile stands up again. It is also made from a single fiber type, so it recycles without separating a glued core.

Which machine knits spacer fabric?

A double needle bar Raschel. The outer guide bars knit each face on its own needle bar and the monofilament bars lap across both bars to tie the faces together. A six guide bar setup is the configuration described in the reference literature.

What monofilament diameter should I use?

There is no standard value. A commercial cushioning sample used 0.2 mm polyester monofilament, while filtration and medical grades go down to 60 μm to 150 μm. Choose by the thickness you need and how firmly the fabric must push back.