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How To Neatly Sew a Separating Zip with a Facing or Lining

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A separating or open-end zipper is a type of zipper that features a special mechanism at the bottom of the zipper teeth which allows the two sides of the zipper to fully come apart and be rejoined. It’s often used on the center front and back seams of hoodies, sweatshirts, vests, jackets, coats, fitted tops, and skirts so that the garment can be fully opened and closed. They come in different materials like nylon, molded plastic, and metal so you can match the material to the weight of your fabric and the style of your project. 

Separating zippers are really easy to sew, and they can add a nice decorative element to a garment and make it look more professional – especially when you use a high quality zipper. They are a great alternative to a button or hook & eye closure, and you can use them on any project that requires the finished product to be completely opened and closed.

Contents list:

What is a separating zipper?

white separating zip shown open and closed
Photo credit: Nisan Aktürk.

A separating zipper is a type of zipper that can be fully separated and rejoined. The teeth can be made out of all the common zipper materials: nylon coil, molded plastic / VISLON, or metal. These zippers are used for projects where you need to completely open the garment and take the two sides apart, such as hoodies, jackets, cardigans, vests, coats, and really fitted tops like corsets. 

What does it look like?

A separating zipper looks like a regular zipper apart from the very bottom. At the bottom of the teeth, there’s a small, box-shaped mechanism on one side, and a longer metal or plastic piece on the other side. When separated, the slider and the zipper pull will remain on the side with the box-shaped mechanism.

Parts of a separating zip:

Separating zippers have 8 parts, with 3 of them being unique to this type of zipper:

  • Insert pin: The insert pin is located at the bottom of the teeth, on the side of the zipper that can be taken out of the slider. It helps you guide the teeth back into the slider when you want to close the zipper.
  • Box pin: The box pin is located at the very bottom of the zipper teeth, on the side of the zipper that cannot be taken out of the slider.
  • Retaining box: The retaining box sits at the bottom of the zipper, on the side without the insert pin (and with the box pin). It’s a small, box-shaped part that has a hole for the insert pin. It functions as the bottom stop for separating zippers, preventing the slider from detaching from the zipper. 
  • Top stops: The top stops are small plastic or metal parts that are at the very top of the zipper teeth on each side of the zipper. They stop the slider from sliding too far up and sliding out.
  • Teeth / elements: Zipper teeth (which are also called elements) are the small parts on both sides of the zipper that engage with each other to open or close the zipper when they pass through the slider. They can be made out of metal, nylon, or plastic depending on the type of zipper you get. 
  • Slider: The slider is the moving part that joins the two sides of the zipper together. Its function is to open and close the zipper teeth as it’s pulled up or down.
  • Zipper pull: The zipper pull is the part that you grab when you want to open or close the zipper. It’s attached to the slider so that you can easily move it up and down.
  • Zipper tape: Zipper tape is the fabric tape onto which the teeth are mounted. It’s most commonly made out of polyester, but there are some cotton options out there. 

Separating zipper lengths:

You can find separating zippers in all sorts of lengths, but they tend to be most commonly stocked in longer lengths because they are often used for making outerwear pieces. Some common lengths you’ll find are 26”, 36”, and 46” (66 cm, 91.5 cm, and 117 cm) but they can be shortened into whichever length you need. Check out our article on how to shorten zippers for a step-by-step tutorial

Uses:

  • Hoodies
  • Jackets
  • Winter coats
  • Vests
  • Corset style or fitted tops that need to fully open on the center front or back
  • Skirts

What is a dual or two-way separating zipper?

A two-way separating zipper can be opened from the top and the bottom, as it features the separating mechanism that’s usually found at the bottom of a separating zipper on both ends. There are also two sliders and zipper pulls, which can be arranged to face each other or away from each other. This style of separating zipper will allow you to unzip different sections from the top and the bottom of your projects, giving you the opportunity to fully customize how your final product looks. 

Preparation:

What is a zipper foot? 

A zipper foot is a special presser foot that allows you to get closer to the zipper teeth with your sewing machine’s needle. While a standard presser foot would have to step over the zipper teeth, a zipper foot glides next to the teeth for an easier installation.

There are different styles of zipper feet for domestic machines, but most of them feature cutouts or notches on the left and right so that the foot itself curves around the zipper teeth as you sew. With these models, you’ll need to snap them onto your machine’s ankle from the right or the left depending on which side of the zip you’re sewing on. Some manufacturers include a designated left and right zipper foot rather than a combined one, so you’ll need to switch between the two depending on which side of the zipper teeth you’re sewing.

How to install it on your sewing machine

  1. Remove the existing presser foot on your sewing machine. On my machine (a Pfaff Ambition 630), this is done by simply pushing the presser foot down from the front, but on some machines (like my old machine, a Singer Promise 1412) you need to pull the presser foot release lever to drop the existing foot.
  2. Next, decide on which side of the zipper you’ll be sewing on. If you’re going to start by sewing on the left side of the zipper, you’ll need to attach the ankle to the right side of the zipper foot (or the right zipper foot) and vice versa.
  3. Once you know which side of the zipper foot you want to attach the ankle to, you can either push the foot up to the ankle or lower the ankle down towards the bar at the back of the foot until it snaps into place.

Machine settings:

  1. Select a straight stitch with a length of 2.5 mm. 
  2. Position the needle so that it’s close to the zipper teeth. This is done by changing the stitch width or changing the needle position. Make sure you slowly turn the handwheel towards yourself to check that the needle isn’t hitting any part of the zipper foot and that it’s sewing close to the zipper teeth without piercing the actual teeth. 

Preparing the fabric pieces:

  • Apply some lightweight fusible interfacing to the edges of your fabric pieces, where the zipper will be sewn. The interfacing strip should be slightly wider than your seam allowance. If you’re using a narrower strip, you can center the strip along the stitch line. 
  • If you’re not going to be using a front-facing or a lining, finish the raw edges of the fabric where the zipper will be attached (i.e. the center front of a jacket). You can use a serger/overlocker machine, a faux overlock stitch, bias binding, or pinking shears depending on the type of fabric you’re using and the project you’re working on. 

Preparing the zipper:

  • Your zipper should be the exact correct length before you start the sewing process. Depending on the pattern you’re using, you’ll need to leave some room above and below the zipper so that the top and bottom edges of your project can be properly finished with a hem, a collar, a waistband, a hood, etc.
  • Once you know the length your zipper should be, carefully measure and mark this distance on your separating zipper, measuring from the very bottom of the bottom stopper / box mechanism. Make a second marking about 1” (2.5 cm) above your first mark. 
    • If you’re using a molded plastic or metal zipper, remove the zipper teeth between the two marks and then cut off the excess length at the second mark.
    • If you’re using a nylon coil zipper, just cut off the excess length at the second mark.

Make new top stoppers using your preferred method, and you’re done! 

For more details, read our tutorial on how to shorten zippers and make different types of stoppers.

Supplies:

These are the supplies you’ll need for a basic separating zipper installation. I’ll include any additional supplies you’ll need for the different methods at the beginning of each tutorial section.

  • A separating zipper in a length that matches the open edges of your project.
  • Two pieces of fabric (to be connected by the zipper, like the two front pieces of a jacket).
  • Fusible interfacing (applied to the open edges).
  • Zipper foot.
  • All-purpose polyester sewing thread.
  • Heavy duty or topstitching weight thread for the topstitching (optional).
  • Iron.
  • Sewing pins.
  • Sewing machine.

How to sew a separating zipper (tutorial):

This is the basic way to sew a separating zipper to your project. It involves machine basting the zipper into place, folding it out, and then topstitching it to further secure it. It’s a really simple way to add a zipper closure to any project where you need the piece to fully open. This technique will leave you with exposed zipper teeth, as well as some visible zipper tape.

Uses

  • Unlined jackets, hoodies, coats, and vests.

Step-by-step instructions:

  1. Unzip your zipper and separate the two sides. 
  2. Lay one side of the zipper on the edge of your fabric, with the right sides facing eachother. The zipper teeth should be facing toward the rest of your fabric, and the edge of the zipper tape should be facing the edge of your fabric. The top and bottom stoppers of the zipper should be perfectly aligned with the top and bottom marks you’ve made on your fabric.
  3. Pin or hand-baste the zipper into place. Fold the excess zipper tape at the top of the zipper diagonally towards the edge of the fabric for a cleaner finish at the top.
  4. Using a zipper foot and a straight stitch with a length of 2.5 to 3 mm, sew the zipper to the fabric. Make sure you’re following the correct seam allowance here, and don’t get too close to the teeth. Otherwise, you might have trouble closing the zipper. Backstitch at the beginning and the end. 
    1.  Maintain the diagonal fold at the top as you sew.
    2. When you’re sewing the side of the zipper with the slider and the pull, you’ll need to stop a little before you reach them to move them out of the way. To do so, stop with your needle in the down position, lift up the presser feet, and slide the slider toward the back. Put the presser foot back down and continue sewing. 
  5. Remove any pins or hand-basting stitches that are left, and flip the zipper out so that the zipper teeth are facing out. The fabric should naturally fold along the stitching line. 
  6. Finger press or iron this fold. Some fabrics like quilting cotton or linen work great with finger pressing, while others like wool or knits require additional heat, weight, and steam.
  7. Using a zipper foot and a straight stitch with a slightly longer length of 3 to 3.5 mm, topstitch / edge stitch along the fold. Your stitches should be about ⅛” (3 mm) away from the fold. 
  8. Repeat steps 2-7 on the other side of the zipper, making sure it’s aligned with the first side on the top, bottom, and any other important points.

Tips:

  • Because the two sides of separating zippers can completely detach, it’s important to pay attention to keeping the two sides aligned when you’re sewing them. If your project involves specific points along the zippered edge (like where the pockets start and end, where the waistband hits, etc.) you can use these points as register markings. To do so, simply lay one side of your zipper on one side of your opening, and mark where these points land on the zipper tape. Close your zipper, and transfer the markings on the first side to the second side. Make sure the markings on both sides match up with the corresponding points on your project as you’re sewing the two together.
  • When you’re doing the topstitching on Step 7, you can use a heavier-weight thread (such as the Heavy Duty line or the Topstitching line from Gütermann) for a more professional finish. If you don’t have a heavier-weight version of the thread color you’re using, you can also wind some to a spare spool, and thread the two strands of thread together through your sewing machine. 

How to sew a concealed separating zipper:

If you don’t want to have the zipper tape and teeth showing too much on your project, you can use a centered zipper application to sew your separating zipper. You’ll often see this technique being used on hoodies, jackets, and coats, where two flaps of fabric meet at the center to hide the zipper underneath.

This technique involves basting the two sides of the fabric together along the center front or back, placing the zipper right side down and centered on the back of the basted seam, and topstitching it into place on either side from the right side. For a more detailed tutorial, check out our article on how to neatly sew a centered zipper.

Tips for sewing a separating zipper to stretchy fabric:

Sew the two sides in the same direction 

When you’re sewing the second side of your zipper, make sure you do it in the same direction as the first side. Meaning, if you sew one side from top to bottom, sew your second side from top to bottom as well. This will prevent ripples from forming in opposite directions around the zipper.

Don’t pull on the fabric

As you’re sewing the zipper, make sure you’re not pulling on the fabric. If you stretch the fabric as it’s being stitched to the stiff zipper tape, you will end up with unwanted gathers and ripples.

Stabilize with knit interfacing

Apply some lightweight knit interfacing along the edges where the zipper will be sewn. The added stabilization will give you neater results while still allowing the fabric to stretch.

Use a walking foot

If you have one, using a walking foot would be a great idea for sewing a zipper to stretchy fabric. Because it moves the two layers of material at the same pace, you’re less likely to experience issues with one layer stretching out or gathering.

Hand baste before you sew

A simple way to make sure the zipper is laying flat on the fabric is to hand-baste it into place before you sew your permanent stitches. Make sure you keep the two layers flat as you’re basting, and only sew them together once you’re happy with how the basting looks. 

How to sew a separating zipper by hand:

If you want to sew your zipper by hand, you can easily do this using simple hand-sewing stitches.

Additional supplies:

  • Hand sewing needle.
  • Thimble (optional, but recommended).
  • Beeswax to strengthen and condition the thread (optional, but recommended).

Which stitches to use?

When you’re sewing a separating zipper, there are two main steps: 

i) basting the zipper into place along the open edge.

ii) folding the zipper out and topstitching the fold into place, securing the zipper.

For the first step (the basting) you can use a short running stitch. If you want an extra secure finish (for instance, if you’re sewing a really tight-fitting top where the zipper will be under a lot of stress), I recommend using a short backstitch even for this step.

For the second step (the topstitching), you can use a prick or pick stitch, which is as secure as a back stitch but looks more minimal and dainty on the right side. For a more visible finish, you can also use a backstitch. Alternatively, if you sew the first step using strong back stitches, you can use a running stitch for a decorative, hand-sewn look. 

How to sew a separating zipper with a facing (tutorial):

If you want a cleaner finish at the center front (or back) edges of your project, you can easily add a facing piece along the zippered edge. This technique doesn’t involve any visible topstitching on the right side of the project, so it’ll also give you a more streamlined look on the right side of your project.

Additional supplies:

  • Facing pieces – I recommend applying some lightweight woven or knit interfacing on the facing pieces, depending on the type of fabric you’re using.

Uses

  • Sewing a separating zipper to a hoodie, jacket, coat, or vest with a facing piece.

Step-by-step instructions:

  1. Unzip your zipper to detach the two sides. 
  2. Lay one side of the zipper on the edge of your fabric, with the right sides facing eachother. The zipper teeth should be facing toward the rest of your fabric, and the edge of the zipper tape should be facing the edge of your fabric. The top and bottom stoppers of the zipper should be perfectly aligned with the top and bottom marks you’ve made on your fabric.
  3. Pin or hand-baste the zipper into place. Fold the excess zipper tape at the top of the zipper diagonally towards the edge of the fabric for a cleaner finish at the top.
  4. Using a zipper foot and a straight stitch with a length of 3.5 – 4 mm, machine baste the zipper to the fabric. Make sure you’re following the correct seam allowance here, and don’t get too close to the teeth. Maintain the diagonal fold at the top as you sew.
    1. When you’re sewing the side of the zipper with the slider and the pull, you’ll need to stop a little before you reach them to move them out of the way. To do so, stop with your needle in the down position, lift up the presser feet, and slide the slider toward the back. Put the presser foot back down and continue sewing. 
  5. Remove any remaining pins or hand-basting stitches, and place the facing piece with the right sides of the two layers of fabric touching. The edges should be aligned, and the zipper should be sandwiched between the two layers of fabric with the teeth facing towards the bulk of the fabric. Pin into place.
  6. Using a zipper foot and a straight stitch with a length of 2.5 mm, stitch the three layers following the previous machine basting line. Sew ever so slightly to the left of the previous stitching so that the basting doesn’t show on the outside of your project. The distance between the two lines of stitching should be less than 1/16” (about 1 mm). Backstitch at the beginning and the end. 
    1. Just like in Step 4, you’ll need to move the slider out of the way when you approach it. Grab the zipper pull from between the two layers of fabric and move it up once you’re about an inch (2.5 cm) away from it.
  7. Fold the seam allowances towards the facing, and press them into place.
  8. Understitch on the facing to encourage the facing to roll towards the inside of the garment and not peek out. To do so, use your zipper foot and a straight stitch with a length of 2.5 – 3 mm and sew ⅛” (3 mm) away from the fold, on the facing. Make sure the seam allowances and the zipper tape are still folded toward the facing. 
  9. Fold the facing in to reveal your finished zipper application. Give everything a final press with your iron.
  10. Repeat steps 2 – 9 on the other side of your project. 

How to sew a separating zipper with a lining:

If your project involves a lining, you can just follow the tutorial above for how to sew a separating zipper with a facing. You’ll just substitute the facing with the lining pieces, first completing the sewing around the zipper (basting, sewing, and understitching) and then moving on to the rest of your lining assembly (such as finishing the neckline, the hem, etc.). You do not need to apply interfacing to the lining pieces.

How to finish the top edge of the raw zipper:

In most cases where you sew a separating zipper, the top edge of the zipper will be hidden under the neckline finish you use. Here are a few examples:

  • If your project involves sewing a hood to the neckline (i.e. a hoodie, hooded cardigan, or a hooded vest), you can enclose the seam and the top of the zipper with some twill tape for an extra clean and professional finish.
  • If the pattern you’re using features a standing collar (i.e. a fleece jacket or a more tailored tweed jacket) the top of the zipper will be tucked into the collar and hidden out of view.
  • If you’re sewing a separating zipper to a fitted top like a corset, the top of the zipper can be concealed within a lining or under a neckline facing.
  • With a skirt featuring a separating zipper, the waistband or the waist facing will hide the top raw edge of the zipper.

In all cases, I recommend folding the top of the zipper tape diagonally so that the raw edge of the tape is already out of the way when you go to finish the top edge of your garment. 

How to sew a two-way separating zipper:

The technique that’s used to sew a two-way separating zipper is identical to the one used for sewing a one-way, regular separating zipper. You can simply follow the tutorials above.

Quick Q&A’s:

What is another name for separating zippers?

Separating zippers are also called open-end zippers. 

Separating vs non-separating zip?

Separating zippers allow you to completely separate two pieces of fabric that are sewn to the two sides of the zipper. Regular, non-separating, or closed-end zippers are connected at the bottom, so the two pieces of fabric will always remain in contact in at least one point. 

Can you turn a closed, non-separating zipper into a separating zipper? 

Unfortunately not. Separating zippers feature a special mechanism at the bottom of the teeth that allow them to join and separate, and this mechanism cannot be fitted into a closed-end zipper at home.

Can you turn a separating into a non-separating zipper? & How?

Yes! All you need to do is remove the separating mechanism that’s found at the bottom of the zipper using pliers, and create a new fixed bottom stop. There are a few ways to make a bottom stop:

  • You can install a replacement metal bottom stopper.
  • You can hand sew or machine sew a thread stopper. 
  • If you’re using a molded plastic zipper, you can melt the bottom teeth together.
  • You can sew a fabric tab for a decorative bottom stopper alternative.

Check out our article on how to make different types of zipper stoppers for more details.

How to replace a separating zipper?

Undo the stitching that’s attaching the zipper to the fabric, and remove the old zipper. Then, just follow one of our tutorials here to reattach a new separating zipper to the now-open edges. If your project involves a facing or a lining, make sure you follow the appropriate tutorial.

Can a separating zipper be shortened?

Yes, you can shorten a separating zipper from the top and maintain its open-end property. The technique you’ll use will depend on the type of teeth (nylon, plastic, or metal) but generally speaking, you’ll need to cut the excess length off the top and create new top stoppers. 

What is the difference between a separating zipper and a two-way zipper?

A regular (or one-way) separating zipper features a single slider & zipper pull and a single separating mechanism at the bottom of the teeth. The slider only moves down, and the zipper only comes apart or together at the bottom. With two-way zippers, you’ll have two sliders, two zipper pulls, and two separating mechanisms: one at the bottom, and one at the top. This allows the zipper to be opened and closed from both ends. 

What is the difference between invisible and separating zippers?

An invisible zipper is almost completely hidden when it’s sewn correctly into a seam, and it’s closed at the bottom so you can’t fully separate the two sides of the fabric. A separating zipper has visible zipper teeth, and you’ll need to follow a centered zipper sewing technique if you want to conceal the teeth. It comes apart at one end, allowing you to fully separate the two sides of your project. 

What to read next:

This article was written by Nisan Aktürk and edited by Sara Maker.

Nisan Aktürk (author)
Nisan started her sewing journey in December 2019 and already has a fully handmade wardrobe. She’s made 50+ trousers, 20+ buttoned shirts, and a wide array of coats, jackets, t-shirts, and jeans. She’s currently studying for her Sociology Master’s degree and is writing a thesis about sewing. So she spends a lot of her time either sewing or thinking/writing about sewing! Read more…

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