Step by step

Sewing an elastic waistband: sewn in or threaded through

The right elastic, the right length, a flat ring and two ways into the waistband: sewn in as on Han and Wleg, or threaded through a casing.

A waistband strip with five marks along its edge, above it a shorter elastic with five marks; arrows connect the points. Part of it is already sewn with zigzag, an arrow shows the stretching

An elastic waistband should hold without digging in and shouldn't twist as you wear it. Three things matter: the right elastic, the right length and neat work.

There are two ways. When it's sewn in, the elastic sits firmly in the waistband and can't twist; that's how we do it on the Han trousers and the Wleg leggings. When it's threaded through, you push it through a casing; that's quick and easy to adjust later. The article Sewing on lingerie elastic shows elastic that sits on the outside edge instead.

What you need

Elastic in the width given in the instructions (e.g. 3 cm for Han, 1.5 cm for Wleg)
Tape measure
Pins or clips and chalk
A large safety pin (for threading)
Sewing machine with zigzag stitch, or an overlocker

Step 1

The right elastic

On the left a knitted elastic with lengthwise ribs, relaxed and stretched, both the same width (right for sewing in). On the right a braided elastic that gets narrower when stretched

Stretch a piece of elastic and watch its width:

Knitted elastic (smooth lengthwise ribs) stays almost the same width when stretched and copes well with needle holes. It's the right one for sewing in.
Braided elastic (small herringbone pattern) gets clearly narrower when stretched and loses its spring if you sew through it. It's only suitable for threading through a casing.

Use the width given in the instructions. Elastic that's too narrow rolls in the waistband; elastic that's too wide puckers the fabric.

Step 2

Finding the right length

On the left a seated figure with elastic around the waist. On the right a piece of elastic with its length marked and a short highlighted section for the overlap

Wrap the elastic around your body while sitting, where the waistband should sit. That's when the circumference is largest. It should lie snug and hold, but not dig in. As a guide you'll usually end up at 85 to 90 % of your body measurement. Our made-to-measure patterns give a guide value on the cover page.

Mark the spot and cut with 1.5 to 2 cm of overlap for joining.

Before sewing it in, check that the ring goes over your hips. Otherwise you won't get in later.

Step 3

Joining it into a ring without twisting

On the left two ends of elastic overlapping flat, joined with a zigzag box. Top right a flat elastic ring (right), below it a twisted ring shaped like a figure eight (wrong)

Lay the ends flat on top of each other, overlapping by the overlap amount. Sew them together with a wide zigzag in a small box: forward, back and once across.

Before you sew, check that the ring lies flat. Half a twist in the elastic will show up later as a thick ridge in the waistband, and the only way out is unpicking.

Step 4

Sewing it in: quarters and stretching

This gets the elastic evenly into the waistband:

Quarter: divide the elastic ring and the top edge of the waistband into four equal sections each and mark them. One mark on the waistband is at the centre back.
Pin: match the marks, with the elastic on the seam allowance of the waistband edge on the inside.
Sew: with zigzag or overlocker, stretching the elastic so it lies exactly on the fabric between the marks. Don't pull the fabric itself.

For Han and Wleg the instructions say which edge the elastic goes on.

Step 5

Folding over and topstitching

On the left a cross-section of a folded waistband with the elastic in the fold at the top and topstitching just below it through both layers. On the right the waistband from the outside with topstitching and a short vertical stitch at the side seam

Fold the waistband over so the elastic sits in the fold at the top. Then from the outside, topstitch just below the elastic through all layers with a stretch stitch, stretching the waistband slightly so it lies flat under the foot.

To stop the elastic from rolling in the wash, stitch it down vertically in the seam at the side seams, from the top to the line of topstitching.

Step 6

Or: threading it through a casing

A waistband with two lines of stitching and an opening. Elastic is being pushed through the casing with a safety pin; the other end is secured outside with a pin

For a casing, fold the waistband over and sew two lines of topstitching so the elastic fits loosely between them. Leave 4 cm open at one side seam.

Fasten a large safety pin to one end of the elastic and push it through the casing.
Hold the other end or pin it to the fabric, or it will disappear into the casing.
Pull both ends out, check the length and join into a ring as in step 3.
Let the elastic slip into the casing, spread the gathers evenly and close the opening.