Tips & tricks

Sewing on lingerie and picot elastic

Picot elastic gives underwear a soft, neat finish. How to find the right length, distribute the elastic evenly and sew it on in two passes.

Picot elastic lies on the right side of the fabric along the edge, the picots point towards the fabric, a zigzag runs right next to the picots, arrows show only the elastic being stretched

The waistband of underwear like the Liv shorty doesn't have a cuff, just a narrow elastic. It holds without digging in and looks pretty with its little loops along the edge. It's sewn on in two passes: first onto the right side of the fabric, then folded to the inside and topstitched.

That sounds fiddly, but it's very doable if you test the length first and divide elastic and fabric evenly. Try it on a scrap first, then you'll know how much tension your elastic needs.

What you need

Picot elastic or flat lingerie elastic, about 1–1.5 cm wide
Fabric scraps for testing
Pins or sewing clips
Chalk or a disappearing marker
Tape measure and a safety pin
Jersey or stretch needle for the machine

Step 1

Which elastic, which side to the skin

Three elastics: picot elastic with little loops along one edge and a brushed back, smooth flat lingerie elastic, and fold-over elastic with a centre groove folded around a fabric edge

For underwear there are mainly three kinds:

Picot elastic: has little loops along one edge, the picots, and a soft, brushed back. The soft side goes against the skin.
Flat lingerie elastic: smooth, without loops. It's sewn on the same way. If it has a softer side, that one goes against the skin too.
Fold-over elastic: has a groove down the middle and is folded around the fabric edge. It encloses the edge instead of being turned under.

The steps here are for picot and flat lingerie elastic. Fold-over elastic is sewn much like Binding edges with bias tape.

Step 2

Find the length

Left: a hip silhouette with elastic at the waist, arrows show it has to stretch over the hips. Right: the elastic is a little shorter than the fabric edge, with a piece for the overlap marked at the end

There's no fixed percentage, because every elastic stretches differently. So: measure and test.

Wrap the elastic around your body where the waistband should sit. It should feel snug but not tight.
Check that it pulls over your hips without reaching its limit.
The elastic usually ends up a little shorter than the fabric edge. That's right, it gathers the edge slightly when worn.
Add 1 cm for the overlap.

If the instructions give a length, use it as a starting point and still check it.

Step 3

Join into a ring without twisting

Left: the elastic ends overlap and are sewn with zigzag. Right: the ends butt together on a small piece of fabric and are zigzagged down

Before you join the elastic, lay it flat and check that it's not twisted. All the picots are on the same side, and the soft side faces the same way all round.

Then you have two options:

Overlap: lay the ends 1 cm over each other and sew across with a wide zigzag, back and forth.
Butted: cut off the 1 cm allowance, place the ends right next to each other on a small piece of fabric and zigzag both onto it. That's less bulky.

The join goes at the centre back or a side seam later.

Step 4

Quarter the elastic and the fabric edge

Top: a smaller ring of elastic, below: the larger fabric edge, both with four marks, dashed lines connect the matching quarters

So the elastic gathers evenly all round, divide both the elastic and the fabric edge into four equal parts.

Elastic: lay the ring flat with the join at one end. Mark the other end. Then put the two marks on top of each other and mark the two new ends.
Fabric edge: the same. Side seams and the centre front and back help you here.

In the next step you pin quarter to quarter. Between the marks the elastic is shorter than the fabric, and you even that out while sewing.

Step 5

First pass: sew onto the right side

Place the elastic on the right side of the fabric, soft side up. The straight edge lies level with the fabric edge, and the picots point towards the fabric. Pin the quarters together.

Sew along the elastic with a narrow zigzag right next to the picots. Stretch only the elastic as you go, until it's as long as the fabric up to the next mark. Just let the fabric feed along and don't pull it.

At the end, sew a little way over the start.

Step 6

Second pass: fold over and topstitch

Left: a cross-section, the elastic is folded to the inside together with the fabric edge. Right: the view from outside, only the picots peek over the edge, with a three-step zigzag below

Fold the elastic to the inside, onto the wrong side of the fabric. The fabric edge folds over with it. From the outside, only the picots now peek over the edge, and the soft side lies against the skin.

From the right side, sew over the flat strip of elastic with a zigzag or three-step zigzag, so the stitches catch it securely right down to its lower edge. Again, stretch only as much as needed for fabric and elastic to lie flat.

Finally, try it on: does the waistband pull on easily, and does it lie smoothly?