What are Underlay Stitches for Embroidery & Digitizing?

Underlay stitches are simply running stitches placed in certain places, at certain directions, with varying stitch lengths to give an embroidery object (satin and fill stitches) a solid foundation.

Underlay is literally the foundation of your digitized embroidery designs. Just as a foundation for a house is vitally important, so is underlay in your design. Underlay stabilizes all the elements of your design before the visual stitches are laid. When you hoop your stabilizer and fabric, there may be some play and movement between the two. The idea is to bind them together and the underlay assists in minimizing distortion.

Underlay fabric & stabilizer example

The underlay also helps minimize the possibility of the embroidery puckering once it’s done and out of the hoop.

Underlay helps keep all your digitized objects well defined, and it will actually make your top stitches look more clean and crisp. Underlay also allows you to build up layers of embroidery on top of each other while decreasing the densities and keeping your design clean.

Why are Underlay Stitches so Important?

The first thing I’m going to do is show you how underlay works and why it’s important to know how to place underlay stitches. We’re going to show 3 simple column stitches using a satin stitch.

In the first example (see image below), we’re using a running stitch and placing a couple passes of underlay right in the middle of the object. What usually happens is that this satin stitch will look a little jagged when it is stitched and won’t have a crisp clean look. I’m sure you’ve probably looked at a finished sample that’s come off your machine and wondered why it doesn’t look clean. It’s not that your machine needs an overhaul, it’s because the underlay was in the wrong place.

Underlay down center

In the second example (see image below), we have the same column stitch. But this time, the underlay is placed very close to the edge of the satin stitch. This placement will have disastrous results as the underlay stitch may pop outside the satin stitch, and then you have to painstakingly pick out all those undesired threads.

Underlay to close to edge example

In the last example, we place the underlay in a specific place, exactly .4mm away from the outside edge of the object. When you run this sample on your machine, you’ll see that the embroidery stitches out crisp and clean, with the underlay acting as a break wall.

Underlay done properly example

The diagram below is a side view of what is happening. The top thread is going to pull towards the center of the column, but the underlay stitch will stop it dead in its tracks, so it won’t pull in any further.

Underlay Side View

This especially helps when you’re stitching designs on loosely woven fabric types. A woven fabric, like the fabric of a golf shirt, would look like a series of hills and valleys from the side if placed under a microscope. Because of their nature and the way these fabrics are milled, they tend to stretch more horizontally than vertically as garments are sewn/constructed in this manner. Thread might fall on either side of a hill or valley even if it appears perfect on your computer screen. Properly positioned underlay will greatly reduce the likelihood of this type of distortion happening.

Underlay Side View #2

The Different Types of Embroidery Underlay

The different types of underlay are center-run, edge-run, zigzag, double zigzag, fill-stitch underlay and combinations of underlay used together. Determining the combination and the order in which they stitch will be determined by both the application and fabric types.


Center-run underlay is used on very small column satin stitches ranging between 1.5mm-2mm. They run directly through the center of the object because of the limited space involved.

embroidery underlay with satin stitches


Edge-run underlay is used when the column stitch gets a little wider and needs more of a foundation, ranging from 2.5mm-3.5mm. This type of underlay provides the break wall effect we covered earlier.

edge run underlay embroidery stitches

Zigzags and Double Zigzags

Zigzags and double-zigzags are generally used along with an edge-run underlay. These are used when applying underlay to a column width of 4mm and up. Because the column is wider, it leaves an area between the column stitches that has no foundation. If there is no zigzag securing the empty space, the column stitch will experience too much pull (for a previous blog post explaining push & pull compensation, click here). It is important to note that it does matter in which order the two underlay types are laid down. The zigzag need to go down first to secure the fabric and the edge run is placed. If you do the opposite, the zigzag will pull in the edge run and it will no longer serve its purpose of being a specifically placed break wall.

zig zag underlay embroidery stitch


Fill-stitch underlay is a running stitch that runs back and forth in an opposite direction of the fill stitch being placed on top. This underlay type secures the area in which the full stitch is being placed. Placing it in the opposite direction helps to reduce the amount of pull in the design.

fill stitch embroidery underlay

If a filled object is not being outlined with a satin stitch and is left as an open edge, then using a combination of fill-stitch and an edge run underlay will help both secure the foundation of the fill and will also promote clean lines around the edges of the fill.

Stitch Length

Underlay stitch lengths generally depend on the nature of the material/fabric being embroidered on. The standard stitch length I use for most underlay applications is 2.5mm. I will lengthen the stitch length if I’m embroidering on fleece, terrycloth, leather, vinyl or any other medium that may cause short stitches to sink in / cut the fabric and disappear, prohibiting them from doing their job.

Using Underlay Techniques for Quick Fixes

Many times, I’ve seen designs that have poor registration simply because underlay has not been used properly to secure the design. This can be especially evident with larger jacket back designs. If you look at how fabric and stabilizer is placed within a hoop, you’ll notice that you can have some play between the fabric and the stabilizer.

embroidery underlay tutorial

If you place a running stitch in a horizontal direction it will help secure the fabric to the stabilizer and smooth out the area prior to all the top stitches of the design being placed. This is a good practice for digitizing large solid designs with a lot of fills and details. Quite often, this technique can also work with designs that have already been digitized and are having registration problems.

Underlay in Embroidery Software

This quick edit technique is also very effective with finish caps. Caps can be one of the most difficult items to digitize for and embroider on because the surface of the hat is not flat. Digitizing for a curved surface is an entirely new subject onto itself, but what do you do if you’ve been given a design that is not registering properly and my not have been digitized properly for a curved surface? In this situation I would bring the design into my digitizing software, keep in mind that I am going to digitize a running stitch right on top to the designs.

The first thing I would do is digitize 4-5 vertical running stitches up and down on the very center of the design. The reason why is because in the very center of any 6-panel cap is the seam, that center seam is the Bermuda Triangle of embroidery! You can lose a letter i in the seam of a cap and if your running a fill stitch horizontally, the stitch can change in appearance when they go over the center seam. We call it stitch in the ditch, the running stitch going up and down a few times will fill in the center seam and the embroidery will then look flatter in that area.

Once I’ve digitized the vertical stitch then I’ll next start to digitize a horizontal stitch from the center out (maybe 10-15mm to either side). Then I’ll do the next pass 20-30mm and so on. Think of it as moving back and forth slowly smoothing out the curved surface from the center and eventually hitting the outer limits in each direction. This really does help with providing a foundation for designs that may not have been pathed to take into consideration the curved surface of a cap.

I generally leave the underlay stitches I’ve just created as a separate color change and then simply move it up in the stitching order so it embroiders first. If you match the first thread color as close to the color of the cap it’s a good safeguard. If any of those stiches are exposed after the design is finished embroidering they will not be noticeable because the colors match.

Applying Underlay in Your Embroidery Software

Many brands of software in today’s market allow you to choose and control the type of underlay and the properties assigned to the objects you create. This is where I feel most embroiderers really struggle. It can be difficult to learn which underlay to use for specific stitch types, the width required based on the objects being digitized and the settings for all the varying fabric types available to sew on. To be fair, knowing all the correct values requires tons of experience.

Now rather than wasting time trying to figure out the rules of underlay for yourself, or trying to piece together dozens of videos / articles posted online like a broken jigsaw puzzle, if you really want to understand how to use underlay, allow me to make it easy for you… We have a full underlay video guide included as a bonus within the first level of my Digitizer’s Dream Course. This, coupled with using underlay as part of the learning process within the Dream Course, will help you to truly understand how to use and apply underlay like a pro. If you’re interested, click here to learn more about the Digitizer’s Dream Course now. 

Wilcom Hatch Underlay

Now if you’re looking for a software to make applying underlay more automated, I’ve personally been an advocate of the Wilcom platform for decades. Now with the release of Hatch, Wilcom has made their industry leading technology available to embroiderers from all walks of life.

One of the reasons I’m a solid support is that Hatch automatically assigns the correct underlay settings for you. Amazingly, it sets the parameters automatically. It works based on the stitch type and width of the given object your digitizing. It also changes all the properties of a design’s underlay at a click of a button based on the Fabric Type you select for the file to be sewn on. Yes, I said AUTOMATICALLY! This is one of the many reasons Wilcom is the world leader of embroidery software and why most of the commercial embroiderers globally use Wilcom. Now don’t get me wrong, all software brands will allow you to apply underlay to your designs. However, most don’t do it atomatically for you and from what I’ve seen, those that do are not nearly as advanced as Hatch. If you’d like to learn more about Hatch and try the 30 day free trial for yourself simply click here.

Want to see Hatch’s auto underlay in action? Watch the quick video below:

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I hope this article helped you to better understand what underlay stitches are, why they’re so important and the different types available. If you enjoyed this article, please don’t forget to share it with your friends and leave a comment below 🙂 I’d love to hear from you!