Sewing Techniques

Applying Elastic

Elastic comes in many different sizes and colours although by far the most common is the straight edge elastic that comes in white or black, ranging from 3 mm to 8 cm wide (1/8 – 3”).

Elastic is usually inserted into a casing, or stitched to fabric edge at the same time as casing is made. However decorative edge elastic used in swimwear and lingerie is often applied to the fabric surface. 

To determine the amount of elastic needed, measure around body and DEDUCT 25 mm (1”).

Elastic in casing
There are two methods of making casings in which to insert elastic. The first is by extending the top of the skirt or trouser fabric piece to allow for a casing and the second is to apply a casing made from contrast fabric. This can be ribbon, bias binding or simply a strip of fabric. (nb: if using a commercial pattern the extra fabric needed for a casing at waist will be incorporated in the pattern piece.)

HANDY HINT: To avoid difficulty feeding elastic through casing, prepare any seam allowances as follows:

Lightweight fabric – press seam allowances to one side, ensuring all seam allowances within the casing area are pressed in the same direction.

Medium to heavyweight fabrics, press seam allowances open and then fuse a tiny piece of hem webbing between seam allowance and main fabric to hold securely in place.




Method 1 – Extended Fabric Casing
1. Measure width of elastic being used. To do this add 6 mm seam allowance and a further 10 mm (3/8”) ease. Thus for a 25 mm wide elastic you need 41 mm extra extended to top of waist level of skirt or trousers.

2. On lightweight fabrics, turn raw edge of extended waist under and press. On medium to heavyweight fabrics neaten the raw edge by overcast stitch or zigzag stitch and press. Then turn under again along the waistline. Press again.


HANDY HINT: If using a stretch fabric or one that doesn’t fray it is not necessary to tuck raw edge under nor neaten it.

3. Machine stitch close to inner fold, leaving a gap of at least 4 cm (1 ½”) through which to insert elastic.

4. Stitch around casing again, this time 2-3 mm (1/8”) from waist edge

5. Attach elastic to bodkin (needle-like tool with blunt or bobble end) or safety pin and then feed through casing, taking care to ensure the other end of elastic doesn’t disappear within casing. Ease fabric along as you feed elastic through.


HANDY HINT: If you don’t have a bodkin or large safety pin, use a darning needle and insert ‘eye’ first so that the sharp end doesn’t get caught on fabric.

6. Bring start of elastic back out of opening and lap ends by approximately 25 mm (1”). Pin together with safety pin and then if possible, try on garment for size.

7. Machine stitch elastic ends together to hold securely before easing them back into casing. Re-adjust gathers evenly.

8. Finish casing by stitching vertically down through all thicknesses at side seams and centre back seam if applicable. This will help keep gathers even and prevent the elastic twisting in the casing.

METHOD 2 – Applied Casing

This type of casing is used when a self-fabric casing might be too bulky or when the casing is attached to another area of the garment such as at the waist on a dress. The fabric used needs to be lightweight and flexible so bias binding or bias cut fabric is idea.

1. To calculate the width of the casing fabric – determine width of elastic and add 12 mm (1/2”) for seam allowances plus 10 mm (3/8”) for ease. Thus for 25 mm wide elastic, the casing needs to be 47 mm wide (2 7/8”). The length of casing should be enough to go around the garment ungathered plus 3 cm (1 ½”).

2. Turn the long edges of casing to wrong side and press.

3. Working with garment inside out, pin casing in position, overlapping short ends, tucking the top lap end under to hide raw edge.

4. Stitch along the top and bottom edges of casing, stitching through garment as well, working both rows of stitching in the same direction.

5. Calculate the length of elastic needed by measuring body and DEDUCTING 25 mm (1”). Insert the elastic where the casing ends overlap, using a bodkin and taking care that the loose end doesn’t disappear into the casing. Overlap and pin both ends of elastic together and try garment on for fit.

6. Once satisfied with fit, machine stitch elastic ends together and allow to disappear within casing.

7. Finish by stitching vertically through all thicknesses at side seams to help keep gathers even and prevent elastic from twisting.

Quartering Elastic Method
This is a surprisingly easy and quick method of adding elastic to a garment and making a casing at the same time. It is often used for children’s clothing, on casual skirts and trousers, sportswear and lingerie.

There still needs to be an extended piece of fabric for the casing because the elastic is stitched to the top edge of the fabric which is then folded down to form the casing.

1. Neaten top edge of garment ready for elastic application.

2. Determine length of elastic needed by measuring body and DEDUCTING 25 mm (1”). Overlap ends by 25 mm (1”) and machine stitch together to produce a continuous loop of elastic.

3. Divide the elastic loop into four equal quarters and mark with pins.

4. Divide the garment top into four equal quarters, again marking with pins (ie: centre back/front and side seams).

HANDY HINT: If working on a particularly large project, divide elastic and garment into eight equal sections.

5. Matching one quarter mark on garment and on elastic, pin elastic to WRONG side of garment with neatened garment edge and elastic edge together. Repeat for other quarter marks (nb: the elastic will be too short for each section of garment at the moment).

6. Using zigzag stitch, anchor elastic to garment at first quarter mark. Then pull the elastic taut, continue to stitch elastic to garment stretching elastic to fit garment edge. Work quarter by quarter.

7. Fold elastic to inside of garment, effectively encasing elastic at the same time. Pin at quarter marks again.

8. Again using zigzag stitch, machine bottom of casing and lower edge of elastic to garment, stretching elastic between quarter marks to fit garment quarters as before.

Lingerie Elastic – Exposed Application
Pretty elastic used for lingerie is applied to the outside edge of panties etc providing a soft and comfortable fit. Soft stretchy picot edged elastics are ideal for this purpose.

1. Neaten the garment edge (turn under a scant 3 mm (1/8”) or overlock with an overlocker).

2. Use the Quartering Method to divide garment edge and elastic into quarters.

3. Pin straight edge of elastic to garment edge, overlapping edges by 6 mm (1/4”). The elastic can be applied to the underside, just allowing the picot edge to peek out or to the right side as a decorative feature.

4. Machine stitch in place, stretching elastic between quarter marks to fit fabric quarter marks as above.

This article has been written by Wendy Gardiner
Illustrations by Jane Bennett, tel: 023 92 412687

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