WHAT IS IT?
A lapped seam is a type of seam that’s sewn with one side overlapping the other. Instead of sewing the two sides right sides together and pressing them open, one side is turned under and pressed and then lapped over the unpressed side. The seam is then either slipstitched (page link) or topstitched (page link) to close the seam.
Lapped seam detail
Lapped seam on Crescent Skirt
WHEN DO YOU USE IT?
Use a lapped seam when a regular seam would be tricky to sew and turn, for example on corners, curved edges and yokes (page link). It’s challenging to sew seams with very pointed lines, so a lapped seam allows you to press under the points of the corner exactly and then overlap it on top of the other side for perfect corners. If you’re adding design lines to a garment across the body, and the lines are curved or shaped, a lapped seam is a good solution to achieving the right shape.
Tips + Notes
- Lapped seams are hard to alter after they’re sewn, so make sure the fit is right before sewing them. Make a muslin test garment first (page link) to check the fit.
- Change regular garment seams to lapped seams if you are having trouble turning a tidy corner or curve.
HOW TO SEW A LAPPED SEAM
Turn under the seam allowance on the side that’s going to be on top. Choose the side that has the corners and points as your top side. You want the side with any outward curves to be on top to reduce the amount you have to clip into the seam allowance.
Overlap the turned edge on top of the flat side and line up the raw edges. Pin in place. For extra hold, hand baste (page link) along the fold.
Source : The Sewtionary An A to Z Guide to 101 Sewing Techniques + Definitions
About the Author : Tasia ST. Germaine