How to Understitch with Your Sewing Machine

How to Understitch with Your Sewing Machine


Hi, this is Marieke and today we are talking about ‘understitching’. Most of you know the word ‘topstitching’; for securing your facings, topstitching your hood or adding a detailed seam.

But sometimes you don’t want to have a visible seam. Understitching can make a garment looking really professional. I love both options and use them where I think is the best. Today I am showing you how to understitch. It is as easy as topstitching and maybe even easier because you won’t see any stitches at the end.

Well, as I said, understitching is the opposite from topstitching and after you are finished you won’t see any visible stitches from the outside. That’s why some people love lined bodices, because you don’t see any visible stitches.

I am showing you how to get that look with understitching.

As example I used the Oversized Tee Pattern, the boatneck with a facing. For facings I prefer my regular sewing machine and a simple zig zag stitch. A serger can be bulky, especially at necklines. I have an example from a hoodie too, that one is serged, but my personal preference is a regular sewing machine for necklines.

  1. Sew the facing on as the instructions are saying, Right side to right side and press up the seam allowance towards the facing.



When you used a regular sewing machine and you are working with thicker fabric, you can shorten the seam allowance to 1/8“.

  1. Use a straight stitch. The stitch, also for topstitching isn’t the stitch that’s holding your fabric, so use a long straight stitch, For the boatneck and also for hoodies I mostly use 3.5 length, but longer is absolutely possible.

  1. Understitching is like topstitching, you are working from the right side. So be careful (and feel) and make sure the seam allowance is folded towards the facing all the time.

  1. You have learned to never pull at your fabric, but you are going to do that now. You are spreading the fabric gently horizontal so you can see exactly where to stitch.

  1. Here you can see, close to the seam, at the side of the facing capture the seam allowance all the time.

  1. So, this is how it should look. All the stitches are on the facing, all the seam allowance is folded to the facing and stitched too.

  1. And press! This picture is taken before pressing anything and you can see already it’s rolling in automatically. But still: press

  1. You can secure the shoulder seams to the facing with a couple of handstitches.

  1. Well, that was pretty much it

  1. A look from the inside.

  1. And you can understitch a lot of things, here is an example from a hoodie. Just sew the outer and liner together, press the seam allowance towards the liner and understitch.


(Written by: Marieke de Jonge)