Project 001: How to draft an elastic waistband

Today we'll be drafting and customizing an elastic waistband pattern. And using the Distributive Property along the way.

In today's exercise, we're chatting about how to draft an elastic waistband. There are a lot of different ways that you can approach a waistband design—even something as simple as an elastic waistband. This post starts with a dissection of the elements of a waistband and why I’m choosing to draft it this way. Next, we'll do the math for the height of the waistband pattern piece. Finally, I'll share some waistband variations and ideas for how you can customize the style of an elastic waistband. Let’s dive in!

Waistband Basics

An elastic waistband is essentially a tube or casing (yes, just like sausage) that holds a length of elastic. To reduce bulk inside the casing, the top of the waistband is usually a fold (as opposed to a seam). Our waistband will be folded at the top, with the long raw edges sewn to the top of skirt. These raw edges can be finished using a serger or zig zag stitch and will be visible on the inside of the garment. Again, this is to reduce bulk inside the casing, where the elastic lives.

For this project, we'll be making a two piece waistband. The waistband can be made with two pieces (one front and one back, seams aligned with the side seams) or with one piece (seam at the center back). If I'm making a garment with side seams, I will generally make a waistband with side seams too. It makes lining up the pieces easy. And, it's easier to make size alterations to the waistband. Additionally, if the fabric is on the narrow side, sometimes a one-piece waistband won't fit the width of the fabric.

Most of the time an elastic waistband is made from a rectangle that is folded in half with the fold at the top and the two raw edges of fabric attached to the skirt (or pants). So, to draft our waistband pattern piece, all we need are the length and height of the rectangle.

Drafting the Tiered Skirt waistband

For the waistband pattern piece, we just need two dimensions—a length and a height. The length is determined by the the length of the seam line at the top of the skirt (or pants). We'll talk about that more later. Let’s dive in to the things we need to include when drafting the height of the waist.

A. The height of the waistband is determined predominantly by the width of the elastic. This is usually about 1" to 2". For this example, I'll use A to represent the elastic.

B. Next, decide how much Functional Ease to add to the casing. I like to have at least 1/8" of ease in the casing. If there's no ease, we risk getting a casing that is too small for our elastic. When the casing is too tight, the elastic will start to form a C shape, which I personally find really annoying. Sometimes this happens if our seam allowance wanders or, the fabric could shrink a little bit. I think even a thicker fabric could make the casing tighter.

So, I recommend that if you are drafting your own casing, just add a little bit of wiggle room. That said, if you like a tight casing, go for it. (Btw, in the variations below, I'll talk about Design Ease and how to draft a paper bag style waistband.)

C Finally, we need to add seam allowance.

Once you’ve assigned numbers to A, B, and C you can go on to calculating the height of the waistband pattern piece.

To determine the height of the waistband, first add together A, B, and C. Then because we’re making a folded waistband, multiply by two. (If you need a visualization, scroll back up a couple of photos.)

Mathematically, this looks like (A+B+C)x2 = Waistband Height.

If you think back to your algebra classes, you might remember the Distributive Property. We can also calculate the Waistband Height by solving the formula

2A + 2B + 2C = Waistband Height.

Either way, you'll get the same answer. So, do whatever makes the most sense to you.

Example Elastic Waistband Draft

Ok, let’s look at a typical example. I’m using 2” wide elastic, 1/8” of functional ease and a 1/2” seam allowance.

A = 2”

B= 1/8”

C=1/2”

A+B+C= 2 5/8” (or 2.625”)

Then, because we’re making a folded waistband, we’ll multiply by 2 and get a Waistband Height of 5 1/4” (of 5.25”).

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Elastic Waistband Variations

Design Ease and the Paper Bag Waist

One really fun way to play with the design of the waistband is to add Design Ease and create a paper bag style waistband. If you're not familiar, the paper bag waistband has extra fabric above the elastic. The elastic (or other cinching) of the waistband creates a dramatic ruffle at the top of the waistband. The more design ease you add, the more dramatic that ruffle will be.

To calculate the height of a paper bag waistband pattern piece, you’ll need to one more element “D” for Design Ease.

The formula is then (A+B+C+D) x 2 = Waistband Height.

Or, 2A + 2B + 2C + 2D = Waistband Height.

See the image below for the formula.

Multiple rows of elastic

This is a really clever idea that I've read about but never tried myself. Instead of making one casing and having one piece of elastic, you can make multiple casings in the waistband for multiple loops of elastic. From what I read, this is a good method if you want to vary the circumference of pieces of elastic. For example, if you have a narrow waist, you can use a slightly smaller piece at the waist, and then a bigger piece on the low waist. This is a great way to get a more custom fit than if you were using a 2 or 3 inch wide elastic.

This is also a good option if you want to vary the design or if you have a stockpile of 1/2 inch elastic that you want to use up.

Add a drawstring

If you'd like a drawstring at the waist, you can sew two buttonholes or set two eyelets at the center front.

Topstitching

A fun way to add design details to your waistband is with topstitching. You can topstitch directly through your elastic (make sure to stretch it as you sew). Generally, I'd do two parallel rows of topstitching. If your elastic is really wide, you might try three rows.

You can also topstitch only through the fabric. If stitching through elastic makes you nervous, this is a great alternative for adding extra detail at the waistband. In my Lela Skirt pattern, I added .25" of ease and then topstitched above the elastic through the fabric only, to make a micro paper bag feature.

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I hope you enjoyed this post and found it helpful. Stay tuned for next week when we dive into gathers and ratios. You can support this newsletter by sharing with friends and clicking the “heart” symbol at the top or bottom of this page.

Happy sewing!

Beth