Adding Zippers to Polartec (or any knit fabric)

Zippers!! A lot of people are afraid to tackle a zipper, but don’t be! They definitely take some practice, but they really aren’t that hard to do. This tutorial will help walk you through the process with some tips and tricks for getting the perfect zipper. Some of the instructions and photos may vary based on your type of sewing machine, so definitely consult your manual as needed, but the basic steps still apply for sewing zippers onto Polartec or any kind of knit fabric.

My son lives in t-shirts and hoodies year round, so I wanted to make him a new hoodie from the gorgeous new Heathered Gray Polartec PowerStretch from Phee Fabrics. I chose the Ziggi Zipper Hoodie from Wardrobe By Me, and went with one size bigger than his measurements so that he had some room to grow.

Let’s get started!

When adding a zipper to knit fabrics, I always use stabilizer to keep the fabric from stretching out of shape while sewing the zipper in place. You are working with a non-stretch material (the zipper tape) and trying to make it fit a stretch material…trust me, stabilizer is your best friend here!

You will need something that is suitable for knit fabrics. My go-to stabilizer is Shape-Flex, a.k.a. SF101, from Pellon.


After you have cut out your garment pieces, you will apply the stabilizer to the edges of the fabric that will be attached to the zipper. For my hoodie, that means I attached a small strip of interfacing to the wrong side of the front center pieces and also to the front center edge of the facing pieces (also on the wrong side). You don’t need a lot of stabilizer here…just a strip about .5″ – .75″ wide and as long as the fabric (minus the SA if desired).

Be careful when fusing the stabilizer! Make sure you follow the manufacturer’s directions and that you are not going to “melt” your fabric. I like to take a scrap of the fabric and a scrap of stabilizer and test it first before trying with my “real” fabric. For the Polartec PowerStretch, I definitely needed to use a pressing cloth so that the high heat and steam needed to adhere the stabilizer wouldn’t damage my fabric.


Once you have your stabilizer attached to the necessary pieces, follow the instructions to assemble your garment up until adding the zipper.

I HIGHLY recommend basting your zipper before stitching – especially if you are working with a facing as well. My hoodie also has kangaroo pockets that I wanted to make sure were lined up correctly.

Take your zipper and place it face down on the right side of your fabric. Here I’ve used clips to hold it in place.


I’ve also marked the top of my zipper outside of the SA. Since I’m using a longer zipper, I will have to shorten it, but I always wait until after I have added the zipper to do so. Also, since I’m using a metal zipper, I need to be extra careful that I’m keeping the zipper teeth out of the SA. Stitching or serging over a metal zipper could damage your machine! I’ve marked my zipper about .5″ down from the top of the front piece, as this pattern has a .25″ SA.


When sewing your zipper, you are going to use a straight stitch. For basting, you don’t even need to switch to your zipper foot yet. I have a narrow teflon foot that I use 90% of the time, and it’s small enough that I usually don’t bother with my zipper foot unless I’m using a zipper with 1″ zipper tape. Then the zipper foot is handy. I also use Microtex needles, which are super sharp and help get through the zipper tape.

For basting, just choose a long straight stitch. I set mine to about 5.


Now, baste the zipper to the first side of your hoodie. Make sure you stay within the SA. In other words, the SA for my zipper is .25″, so I basted at about 1/8″.



Once you have that side basted, unzip the zipper and place it face down on the right side of the other front edge.


Again, you want to mark the top edge the same amount as the other side. Now, while it’s still clipped, you can zip the zipper up and check the alignment. As you can see in the following pic, my bottom hem and the pockets were not aligned.


To fix that, I take my ruler and line it up with the seams on each side and then make a mark on the zipper tape where the seams need to be on the un-basted side.

Now unzip the zipper again, and line those marks up with the corresponding seams and reclip the zipper to the fabric.


Baste the zipper to the second side in the same way as you did the first. Once it’s basted, zip it up and check that everything is still lining up. Perfect!


If things are still not aligned, you can easily take out the basting stitches and shift things around. Once you have everything where you want it, it’s time to sew it in place.

Now is the time to change over to your zipper foot and also set your stitch length shorter – about 2.5-3. My pattern calls for facings, so here I have lined up my facing on top of the zipper before sewing.


Stitch through all the layers to sew the zipper to the garment.

When sewing the side with the zipper pull attached, you may need to move the zipper pull out of the way in order to manoeuver around it. To move the zipper pull, make sure the needle is DOWN and in the fabric, then raise the presser foot, shift the garment, and slide the zipper pull out of the way of your stitching.


Once you have moved the zipper pull, shift the fabric back into place, lower the presser foot, and finish sewing.

And there you have it – your zipper is installed! Easy peasy! 🙂


I hope you have found this helpful, and I look forward to seeing what you make with all of the awesome Polartec fabric from Phee Fabrics!