Lapped zipper construction

This is the 3rd part of the 4-part series regarding the process review of the lapped zipper. The first entry analyed the correct application of a lapped zipper. The 2nd part was the pattern templates needed to execute the proper insertion; this the latter being part 3. The 4th part is still to come. This will detail the specifications of the draft (of part 2) so you can replicate this effect on applicable styles you produce in the future.

Before I begin, I should mention there are standard seam allowances that are used in any professional shop. Unlike home sewing, our seam allowances vary depending on where the stitching is. For example, the most common seam allowance is 3/8″. The neckline allowance is 1/4″. DEs usually use 1/2″ everywhere and this is a problem because the sewing people aren’t used to doing a special job like that and besides, it’s less accurate too.

If you’re serious about your business but don’t like the industrial weird seam allowance policy and think you’d rather skip it…believe me, I sympathize. All of the do’s and don’ts get tiring after awhile and you’re not sure which ones really matter but all I can say is that this one matters. Any quilter will tell you the same, so pick another battle, this isn’t one of them. Accordingly, all allowances in this demonstration are 3/8″ except the neckline which is 1/4″.

Here the facings are laid out, pattern face up and fabric face up. When a piece says “face up” you can’t flip it (unless the wrong side of the fabric is up). In subsequent photos you’ll see that my facings are fused (recommended).

The left and right backs are cut and marked. Please note the left back has a notch at the neckline (it’s 3/4″ from the cut edge). There’s a dot at the CB seam which corresponds to the metal zipper stop. You’ll notice that the zipper in this sample was manually shortened because I didn’t have a contrasting zipper in the correct size. I went to a lot of bother to use contrasting colors for all layers so the photos and pieces concerned would be clear and evident.

Sew up to the dot -which is not visible because yours truly marked the wrong side.
But no matter, you can see the dot here.

Matching edges evenly together, join the appropriate sides of the zipper to the right and to the left. Do not be alarmed that the zipper does not lie flat if closed.
Both sides are completed.
Matching all edges and layers evenly together, sew the right facing to the right side and then the left facing to the left side along the zipper tape. You may notice -on the left- that the facing shoulder seam does not evely match the left back shoulder seam. This is not a problem.
Shown from the opposite side, this is more obvious.
Topstitch the facings and all seam allowances toward the zipper tape (away from the body).
This is where it gets interesting. Remember that neckline notch on the left side? Fold the shell back on that notch (right sides together) and sew the left neckline.
Repeat for the right side except there’s no notch because you fold that side as tightly as you can. Stitch the right side of the neckline.
Trim the corners, make note how the top of the zipper tape has been cut off to assist in smooth turning of the neckline seam.

If you have a sewing hammer (a regular hammer would work okay for a test sample), give the top of that neckline seam -on both sides- right on the seam line, a good whack or two and don’t be shy about it. That’s another “sewing secret” those sewing experts never seem to mention (one would think they would have noticed all of the thunking going on) which leads me to believe they’ve never been anywhere near a sewing line at any time in their lives because I don’t know how you could miss that. Oh, just don’t hit any teeth and you’re okay. Whack away.
In this photo, you can see the left side has been turned right side out, lapzip
go ahead and turn them both.
Here’s an outside view of the back neck. It hasn’t even been pressed but you can already see how neatly all of this is going to lie.
I want you to notice something in this photo. Look at the center of the zipper and the center of the seam line. You’ll note that these are not lined up which is good thing because this wouldn’t come out correctly if they had. From here, it looks like the right side of the zipper is hanging off into nothing (with no seam allowance under it) but you know that’s not true.
Here you’ll notice that I clipped into the seam allowance 1/4″ which allows the pleat to form naturally on the top side. It’d still pleat if you didn’t clip it there but it might be evident topside (if you didn’t) on very lightweight fabrics.
The underlap side (right) is topstitched close to the tape. You can see how the zipper is tucked into that overlap from the left side.
This shows all edges topstitched and now it’s done. Also, you’ll notice my topstitching isn’t the greatest but I just can’t ever get used to the light pressure of home machines so it never looks as good but it’d look just fine if the thread matched.

By the way, you should be aware that in the usual order of things -in a sewing line- the piece rate for topstitching is higher than for other jobs. That means that you need to watch how that job is assigned because supervisors are known to assign certain jobs to their friends and that’s not necessarily fair, don’t you agree? Not to say that they always do since I was a topstitcher too and I was never popular anywhere or at any time which should be no surprise to any of you who know and love me ;).

The anatomy of the draft will be the last of this series concerning lapped zippers. After that, I’ll get around to centered zips which are 2-per/mirrored (less costs in pattern and development) and a little easier to draft and the sewing explanation is simpler since both sides are the same.

If this has been useful and will save you some money, I accept gratuities if you’d care to extend them (my paypal acct is my first initial and last name with no spaces at Or if money’s too crass for your taste, I have an Amazon wish list too. If you can only contribute comments and questions, those are sincerely appreciated as well. Thanks.

Process review: lapped zipper
Lapped zipper template
Lapped zipper construction
Lapped zipper specs
Centered zipper template
Centered zipper construction
Invisible zipper tutorial pt.1
Invisible zipper tutorial pt.2
Shorten a separating zipper
Zippered welt pocket tutorial
Deconstructing a zippered pouch
Zippered welt pockets

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  1. Sophie Kats says:

    You are absolutely AMAZING!
    You couldn’t have explained it any clearer if you were standing next to me :-)
    My zips will look professional!
    Much obliged.

  2. Sue Whelan says:

    Fabulous instructions, Kathleen. Thank you. Now I know why my lapped zippers never looked as good as RTW: the instructions were dreadful. I’m going to try using the flat side of my ball-peen hammer (that I normally use for jewellery making) on the corners. The one home-sewing maven who often recommends using a hammer to flatten seams is Sandra Betzina. I always wondered where she got the idea from; now, I know :-)

  3. Yvonne in England says:

    Thank you for this excellent explanation of *how* to pefect this opening. Even when I was at school, I used to tell the teacher that there wasn’t enough fabric on the pattern to make a proper lapped construction. Now I know why. You can’t just use ‘mirror’ pieces for the left- and right-hand sides. I must track down that teacher – its only 40 years ago. ;-)

  4. Monica says:

    Thank you for the wonderful tutorial. Are the shoulder seams supposed to be aligned the right side after attaching the facings to the zipper? I find mine to be about half an inch too long.

  5. Kathleen says:

    Hi Monica, yes they should be aligned neatly. I’m guessing there was an issue with the pattern. Perhaps you cut two of one piece? Each side has its own pattern.

  6. Monica says:

    Thanks, Kathleen! I must have printed it out wrong, because the right facing is a lot longer than the right back.

    It is strange, though — everything else lines up perfectly. In any case, it’s mostly a curiosity for me — your centered zipper tutorial was also enlightening and produced such great results it’s hard to imagine needing another installation method.

    I think I’ve read through most of your archives and your book. I’m a beginning sewist and enjoyed these very much, so thank you for sharing your work.

  7. Kathleen says:

    The only way to really know is to see your sewn sample for comparison. I did another of these a few months ago and it came out a bit off, I later examined it and saw it was because I didn’t take the full allowance so I did it again and it was fine. I know that one other time I did this that it was off but that was because the print out was not set to 100%. I was planning to actually digitize this rather than scanning which would ensure more consistent output but haven’t gotten to it yet. Maybe I can get to it next week.

    There’s another in the forum you might like, a vintage method to create the effect of an invisible zipper. Since you have the book, you could join.

  8. Tina says:

    Kathleen, is there a preferred zipper insertion method for a given garment? Like do you always use the centered zipper application on a skirt or a lapped zipper on a bodice which has a facing, etc.

  9. Pingback: LBS | crab & bee

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