Turn up the hem of an older skirt or a good coat and you will often find a narrow woven tape, maybe half an inch wide, running along the raw edge. It is usually a different color from the garment and a different material altogether. It looks like a repair, or like something left over on the factory floor. It is neither. It is a deliberate hem finish, chosen because the cloth would not take a doubled turn, and it is the first part of the garment that tends to go wrong once the piece has been washed a few times.
What Seam Binding Is Doing on a Hem
A hem has to do two separate things. It has to enclose a raw edge so the cloth cannot fray, and it has to put enough weight at the bottom for the fabric to hang properly. The usual method is to turn the edge under twice and stitch it, which buries the raw edge inside its own fold. That works beautifully on light cotton and poorly on anything thick, because each turn doubles the material and a double turn in heavy wool shows as a ridge.
A seam binding hem solves that by replacing one of the folds with a thin tape. The tape is stitched to the raw edge, folded over to enclose it, and then the whole edge is turned up once and held in place. You get a finished edge with one turn instead of two, so the hem lies flatter against the leg, and you keep the full hem allowance rather than losing an inch of it to folding.
That second point is why binding turns up so often on older clothing and on anything that has been altered. Letting a hem down leaves a short allowance and a hard crease where the old fold used to sit. Binding the new raw edge means the hem can be as shallow as it needs to be. It is a practical finish, used by people who were being careful, and it brings its own set of problems with it.
The Two Materials in One Seam
Most of the narrow tape sold for this job is woven rayon, and rayon behaves very differently from the fabrics it ends up sewn to. It is regenerated cellulose, so it takes up a lot of water, swells considerably while wet, and loses a large share of its strength for as long as it stays in that state. Dry, it is smooth and strong. Wet and under movement, it is the weakest thing in the hem.
Rayon also relaxes the first time it is properly wet. Tape is woven under tension and finished under tension, and that tension stays locked in the structure until water lets the yarns move. The first real soaking releases it, and the tape comes out measurably shorter than it went in. Nobody notices a tape losing length on a reel. Sewn along a hem edge, a loss of a few percent has somewhere very visible to go.
Polyester tape has the opposite problem. It is dimensionally stable, which sounds like the better option, and it is, right up until it is sewn onto cotton or linen that is not stable at all. The shell shrinks over the first few washes while the tape stays exactly as long as it always was. Now the tape is longer than the edge it is attached to, and the surplus has to buckle somewhere.
Why the Tape Ripples After Washing
Take whichever of the two has ended up shorter and follow what the stitching is forced to do. The seam joining tape to raw edge cannot let either side slide. So when the tape contracts, it draws the fabric edge in with it, and the fabric, now carrying more length than the tape will allow, has to absorb that surplus by waving. The result is a hem that undulates gently along its whole run.
Hold it up and the ripple is regular, and it sits at the very edge rather than in the body of the garment. That is the signature of an edge finish that has gone out of step with the cloth. A hem that waves because the fabric was cut on a curve waves unevenly and softly. A hem that waves because its tape has shrunk waves at a steady pitch, more like a frill.
Pressing will flatten it for a while, and it will come back with the next wash, because nothing has actually been resolved. The tape is still short. The only real options are to unpick the tape and replace it, or to accept it as part of the garment. Telling the two kinds of waviness apart is worth something, since one is a fault that keeps returning and the other is simply how the cloth hangs.
How a Hand Hem Stitch Unzips
The upper edge of the tape is usually attached to the garment by hand, with a catch stitch or a blind hem stitch that picks up only a single thread of the shell fabric each time. That is deliberate. A machine line would read as a hard row of stitching on the face, and the whole point of a hand finished hem is that the face stays clean. The trade is that the hem is held by one continuous thread.
A continuous thread is not locked at every stitch. Break it in one place and the two sides of the break can be drawn back out of the fabric by anything that tugs on the loops. In a drum, with a wet heavy hem swinging and catching on itself, that is exactly what happens. One broken stitch becomes several inches of loose hem in a single wash, and it reads as though the hem simply gave way on its own.
Those stitches are also loose on purpose, so the hem can move without printing a line through to the face. A loose loop is an easy thing to catch. The practical consequence is that a taped hem should be checked before it goes anywhere near water. Run a finger along inside the fold. If the thread is broken or a loop stands clear, that break will grow, and a few stitches by hand are much less work than remaking a hem.
Washing and Pressing a Taped Hem
Wash the garment inside out, cool, on a gentle cycle, and give it room. Cool water matters because rayon tape has the most to lose from heat and wet movement arriving together, and room matters because the damage here comes from mechanical load rather than from water itself. A mesh bag stops the hem catching on buttons and zippers, which is where most broken hem threads actually begin.
Weight is the other thing to manage, and it is easy to overlook. A wet skirt or coat is heavy, and if it hangs from its shoulders while soaked, all of that weight pulls down through the cloth to the hem, stretching the edge and loading every one of those single thread stitches. Dry it laid out, or over a rail so the length is supported, and let the weight leave with the water.
Press a seam binding hem from the inside, with the tape edge resting on something soft. A folded towel works well, because it lets the hard line of the tape sink in rather than be pushed through to the face. Pressing firmly over a tape edge from the right side leaves a permanent ridge and a shine along it, since the raised line takes all the pressure and the fibers underneath flatten. Work the allowance, not the face.
Taped Hems in Plano Parker Closets
The clothes that come out of storage for the cool season are the ones most likely to carry a taped hem, because taped hems belong to coats, skirts and dresses that were built to last and then put away. A garment that has sat folded in a Plano closet since spring has a hem creased in one position for months on end, and the thread running through it has not moved an inch in all that time.
Humid spells matter here in a small way. A tape that has taken up moisture from the air sits slacker than a dry one, and the hem edge looks softer and less crisp than it did when it was put away. It firms up again as the air dries out. That is not damage and it needs no fixing, but it is worth not mistaking for a hem that has genuinely failed.
WaveMAX Plano Parker is at 930 W. Parker Rd, easy to reach from Plano and the surrounding area. Garments with hand finished hems want a gentle cycle and space around them rather than a crowded drum. A larger machine running a light load is a far gentler place for a taped hem, because the garment is moving through water instead of being dragged against a packed mass of other clothes.
Gentle Cycles and Room to Move
A coat, a skirt or a good dress with a hand finished hem needs a cool gentle cycle and space around it, not a full drum and a hot wash. Washing a small load in a large machine is the simplest way to cut the mechanical load that breaks hem threads in the first place.
The machines at our self-service laundry on West Parker Road give a hand finished garment the room it needs, since a light load in a large drum moves gently where a packed small one does not, and a cool wash keeps rayon tape out of the wet, warm state in which it is weakest.
Our machines and the store are cleaned daily.
Our wash-dry-fold service covers the everyday laundry.
For general guidance, The American Cleaning Institute publishes a fabric care guide that is a useful cross-check.
The short version
Seam binding is a narrow woven tape stitched over a raw hem edge so the hem needs only one turn instead of two. The trouble is that tape and cloth answer to water differently, so one ends up shorter than the other and the edge ripples at a regular pitch. The tape’s top edge is usually held by one continuous hand thread, which unzips from a single break. Check the stitching, wash cool and inside out, and support the weight as it dries.
WaveMAX Plano Parker is at 930 W. Parker Rd, easy to reach from Plano and the surrounding area. If you have a load that will not fit at home, call us at 214-764-8811.