How to make and sew piping

Piping is a cord wrapped in a bias strip of fabric, sewn into a seam so a thin raised line shows along the edge. To make it, cut bias strips as wide as the cord circumference plus twice your seam allowance, fold them around the cord and stitch close to it with a zipper foot. To sew it in, baste the piping to one piece with its stitching on the seam line, lay the second piece on top right sides together, and stitch again a thread's width closer to the cord so the first row stays hidden.

What is piping and where do you use it?

Piping outlines an edge: the seams of a cushion cover, the collar and cuffs of a blouse, the yoke seam of a shirt, the edge of a pocket or the neckline of a dress. It adds a line of contrast and a little structure, and it hides a seam that would otherwise sink into the fabric. Store-bought piping exists in a few plain colors, but making your own matches any fabric and lets you choose the thickness.

The strip must be cut on the bias, at 45 degrees to the grain, so that it bends around curves and corners without wrinkling. A strip cut on the straight grain will pipe a straight seam but puckers on anything curved. How to cut fabric on the bias shows the quick way to cut long strips from a square.

What do you need to make piping?

• Cord: cotton piping cord, sold by diameter. 3 mm (1/8 in) is the usual size for garments, 5 mm (3/16 in) for cushions and bags, 8 mm (5/16 in) and up for upholstery. Pre-shrink cotton cord in hot water, as it shrinks the first time it is washed.
• Fabric for the strips: a light to medium cotton, lawn or poplin behaves best. Thick fabric makes bulky piping. Allow about 50 cm (20 in) of fabric for 5 m (5 1/2 yd) of strips.
• A zipper foot or a piping foot. A piping foot has a groove under it that rides over the cord; a zipper foot lets you stitch beside it. Both work.
• A rotary cutter and ruler for the strips, and a chalk pencil.

How wide should you cut the bias strip?

Wrap the cord in a scrap of fabric, pin it closed, and measure from the fold to the pin: that is the cord's wrapped half-circumference. Add twice your seam allowance and double the total. In practice:

Cut the strips a little wider if your fabric is thick. You can trim the piping's seam allowance after it is made, but you cannot add to it. The bias binding calculator tells you how much fabric a given length of strip needs.

How do you make piping, step by step?

1. Cut the strips on the true bias with a rotary cutter and ruler. Mark the 45 degree line from a corner of the fabric and cut parallel strips from it.
2. Join the strips. Lay two strip ends right sides together at a right angle, so their cut ends cross, and stitch diagonally from one inner corner to the other. Trim to 6 mm (1/4 in) and press the seam open. The join then runs diagonally across the strip and adds no lump.
3. Wrap the cord. Fold the strip over the cord, wrong sides together, with the raw edges even. Pin every 15 cm (6 in) or hold it as you go.
4. Stitch close to the cord with the zipper foot on the cord side, a 3 mm (1/8 in) stitch length, keeping the needle 1 mm from the cord. Do not pull the strip as you sew: bias stretches, and stretched piping shrinks back later and puckers the seam.
5. Check the seam allowance. Measure from the stitching to the raw edge and trim it to your pattern's seam allowance, so you can line the raw edges up with the garment edge when you sew it in.

Make a continuous length: it is easier to sew a cushion or a neckline with one long piece than to join short ones in the seam.

How do you sew piping into a seam?

1. Baste the piping to the first piece. Lay the piping on the right side of the fabric, raw edges together, so the piping's stitching sits exactly on the seam line. Stitch with the zipper foot directly on top of the piping's stitching, or a thread's width inside it.
2. Clip for curves. On an outward curve such as a cushion corner with a radius or a neckline, clip the piping's seam allowance every 1 cm (3/8 in) up to the stitching so it spreads. On an inward curve, clip the same way so it can open. Clipping and notching curved seams explains which cut goes where.
3. Turn a square corner. Stop stitching 1.5 cm from the corner with the needle down, clip the piping's seam allowance right to the stitching at the corner point, pivot the fabric, bend the piping around the corner and continue. The clip lets the cord turn without a bump.
4. Join the ends. Start sewing 5 cm (2 in) in from the piping's end and stop 5 cm before meeting it. Unpick 3 cm of the piping stitching on the finishing end, trim the cord so the two ends butt together, fold under the raw end of the strip and wrap it over the starting end. Finish stitching across the join.
5. Add the second piece. Place the second piece on top, right sides together, with the piping sandwiched. Flip the work so your basting row is on top, and stitch again with the zipper foot, a thread's width closer to the cord than the basting. This hides the basting row and leaves no fabric showing beside the cord.
6. Press and grade. Press the seam allowances away from the piping and grade them: trim the piping's allowance to 1 cm, the garment's to 6 mm, so the edge lies flat.

Tip: If the piping shows a gap of fabric between cord and seam from the right side, your final row was not close enough. Stitch once more, a fraction closer to the cord; the extra row inside the seam allowance does no harm.

What are the most common mistakes with piping?

• Strips cut on the straight grain. They pucker on every curve. Cut on the true bias.
• Stretching the bias while stitching. The piping shortens later and the seam gathers. Guide the strip, do not pull it.
• A regular foot. It cannot get close to the cord, so a ridge of fabric shows beside it. Use the zipper or piping foot for every row.
• Forgetting to pre-shrink the cord. Cotton cord shrinks in the first wash and puckers the whole seam.
• Bulky joins. Join strips diagonally and never place a join at a corner.

When should you use piping instead of binding or topstitching?

Piping lives inside a seam, so it needs a seam to go in: an edge finished with a facing, a lining or a second layer. Use bias binding instead when the edge is raw and you want to enclose it, as on a neckline or an armhole without a facing. Use a row of topstitching in contrasting thread when you want a line without any bulk, on a shirt yoke or a pocket for instance. Piping is the choice when you want a raised edge with real presence: a cushion cover, which is the classic first project and is described step by step in sew a cushion cover with piping, or the neckline and sleeve hems of a blouse. If you draft a cushion cover pattern in Sewly, the pieces are given as cutting dimensions, so adding piping is a matter of cutting strips to the perimeter plus 10 cm (4 in) for the join.