How to Sew a Lapped Zipper – The Easiest Way

A lapped zipper is one of the most common zipper insertion methods used in sewing. Unlike an exposed zipper, the zipper teeth are hidden beneath a fabric flap, creating a neat and professional finish. Lapped zippers are commonly used in skirts, dresses, trousers, cushions, and other sewing projects where you want a discreet closure. Learning how to sew a lapped zipper is easier than many beginners expect. In this tutorial, you’ll learn how to sew a lapped zipper step by step, including zipper placement, stitching tips, and common mistakes to avoid.

What is a Lapped Zipper?

Lapped zippers have one side of the opening as a flap that covers the other, creating an almost invisible closure. This opening and the way the zipper is inserted give it the name, but the zipper itself is just an ordinary type of zipper. Learning how to insert a lapped zipper is necessary for those placed down the back of a dress or on the side of a skirt. A zipper on the side of a skirt will look less obvious if it is sewn as a lapped zipper. 

If you are learning zipper insertion techniques, read the full how to sew a zipper guide to compare lapped, centered, invisible, and exposed zipper methods.

When to Use a Lapped Zipper

A lapped zipper is ideal when you want a closure that is less visible than a centered zipper but easier to install than an invisible zipper. Common uses include:

• Skirts
• Dresses
• Pants and trousers
• Cushions
• Bags and pouches
• Home décor projects

Because the zipper teeth are hidden beneath a fabric flap, lapped zippers create a clean and professional appearance.

How to Sew a Lapped Zipper (Step by Step)

Here are the steps to take when learning how to sew a lapped zipper:

Step 1 – Choose the Zipper

Check that you have the right length and color zipper to match the opening.  Have the right thread in the right color and use a zipper foot. If your zipper is too long you can cut it, but make sure you either replace the metal stopper or sew a stop bar in its place. Learn how to shorten zippers.

Step 2 – Mark the Position

Check the side of the garment that will be the front and mark it clearly with some tailor’s chalk. This side will be the side of the flap that will conceal the zipper.

Step 3 – Stitch and Baste the Zipper

Mark your seam up to the point where the zipper will be inserted. Ensure you leave enough space at the top to add a waistband or any other seam allowance. 

❤️BEGINNER TIP: Your seam allowance needs to be at least 5/8″ (15mm) so increase it if necessary. I find seam allowances of 3/4″ (2cm) to be the easiest to work with when inserting lapped zippers.

Sew the seam, stopping at the zipper opening. Secure the seam at the bottom with a few extra back stitches because this part of the opening will take the most strain as the zipper opens and closes.

Baste the rest of the opening where the zipper will be placed with your longest stitch (normally 4.0). You can see it as the red thread in my photo.

Step 4 – Sew Zipper First Side

Press open the seam allowance.

Separate the seam allowance for the back of the garment.

Place the opened zipper on the seam allowance with the right sides together (the zipper will face down). The teeth of the zipper should be just to the side of the seam.

Using your zipper foot, baste the zipper to the seam allowance. You will be sewing 3/8-1/4″ from the zipper teeth.

Fold back the zipper and topstitch along the edge. For an invisible finish, use a matching thread color.

Step 5 – Place the Zipper Second Side

Check that the zipper opens and closes easily. Now, you are left with the other side of the seam allowance. 

Do up the zipper and place it over the other side of the seam allowance. Baste or pin this side and press firmly to flatten the edges before you sew.

Step 6 – Stitch on the Outside

Turn the garment to the right side.

Start at the top of the zipper opening and sew straight down this side of the zip using your zipper foot. Allow the fabric on this side to act like a flap covering the zipper’s teeth. 

The width of this side must not be wider than the zipper tape underneath because the machine stitch must secure the side of the zipper flap and the edge of the zipper tape. 

Make sure you mark the exact spot where the zipper ends beyond the metal with a pin or your tailor’s chalk. When you reach this point, leave the machine needle in the fabric and lift the zipper foot. (Careful of any metal underneath as you don’t want to break a needle.)

Turn ready to sew a bar across the bottom. The bar may be a slanted or a straight short bar to end the zipper opening.

Step 7 – Remove the Basting Stitches

Now, you have sewn the complete zipper into the side seam and have made a flap to cover the opening using the fabric in the seam allowance. Remove the basting with a seam ripper and give the zipper opening another press. 

Common Mistakes and Tips for Sewing a Lapped Zipper

Mistake	Tip
Using a seam allowance that is too narrow	Allow at least 5/8 inch (15mm), preferably 3/4 inch (2cm).
Forgetting to baste the opening	Basting keeps the zipper aligned during installation.
Making the flap wider than the zipper tape	Ensure the stitching catches both the flap and zipper tape underneath.
Not reinforcing the bottom of the zipper opening	Backstitch well at the zipper base to prevent strain.
Skipping pressing steps	Press after each stage for a flatter, more professional finish.

Lapped Zipper FAQs

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How to Sew a Lapped Zipper – In Conclusion

The zipper should open and close easily, and the flap part should point toward the back of the garment. The rest of the finish depends on the item you have made.

A skirt will need a waistband, while a dress may have had the zipper sewn in the side to help get the dress on and off easily. If the lapped zipper is in a cushion, it is best to sew the seam with the zipper first and complete the cushion and the other seams after the zipper opening.

You may find that once you have tried this lapped zipper, you will have other uses for it because it neatly conceals the zipper’s teeth —little bags, purses, and pouches all need a neat zippy closure. Try the lapped zipper closure; you will be amazed at its usefulness.