A flat felled seam (also known as a welted seam) is a fabulous finish that looks good from both the front and back. The traditional way of creating this type of seam involves some rather precise trimming, folding, and pressing – picky work that can sometimes result in your fingertips getting awfully close to a hot iron! So we were super excited to learn about the Janome Lap Seam Foot; it does the folding for you, resulting in a perfect lap and stitch in a single pass.
The foot is designed for Janome machines with a top loading bobbin and a 9mm stitch width. It is recommended for medium to heavy-weight fabrics, such as denim, cotton canvas, cotton duck, and outdoor fabrics. If you have a different type of fabric or are simply interested in how to create both outside and inside flat felled seams, take a look at our traditional step-by-step tutorial.
One of the most common examples of a flat felled seam can found on your favorite pair of jeans. The seam is strong and durable with multiple lines of stitching, and it is completely finished with no exposed raw edges. You may have also seen it on unlined jackets.
Besides being an excellent choice in heavy-duty garment sewing, it’s also a perfect seam finish for joining widths of fabric for large tarps and awnings, tablecloths, and shower curtains. Not only is the result nicely finished from both sides of the fabric, it can also be decorative by using contrasting thread for the distinctive parallel rows of stitching.
The Janome Lap Seam Foot is designed to roll the seam allowance to the inside and edgestitch it in place at the same time.
An Outside Flat Felled Seam
To create the more common flat felled seam with two rows of top stitching – what we call an outside flat felled seam, the steps to use the Lap Seam Foot are quite simple.
- To start, place your fabric wrong sides together.
- Stitch a ⅝” seam. We used a thicker topstitching thread in both the bobbin and the needle and sewed this initial seam with the standard A foot. The stitch length was 3.0mm.
- Trim one side of the seam allowance back to ¼”.
- Change the foot to the Lap Seam Foot.
- At one end of the seam, finger press the remaining ⅝” side of seam allowance under ¼” – you just need an inch or two folded under to start the process.
- Place the fabric under the foot and feed the folded side of the seam allowance into the curl of the foot.
- Start stitching, guiding the fold into the foot. Once the stitching is underway, the curl of the foot will continue to fold the seam allowance and stitch it in place.
- Your finished seam looks great from the front…
- … and from the back.
An Inside Flat Felled Seam
To create a flat felled seam with a single row of top stitching – what we call an inside flat felled seam, the process is just as quick and easy.
- To start, place your fabric right sides together.
- Stitch a ⅝” seam. We used all purpose thread in both the bobbin and the needle, and sewed the seam with the standard A foot. The stitch length was 2.6mm.
- Trim one side of the seam allowance back to ¼”.
- Change the foot to the Lap Seam Foot.
- Re-thread with topstitching thread in the bobbin and the needle. Adjust the stitch length to 3.0mm.
- At one end of the seam, finger press the remaining ⅝” side of seam allowance under ¼” – you just need an inch or two folded under to start the process.
- Place the fabric under the foot and feed the folded side of the seam allowance into the curl of the foot.
- Start stitching, guiding the fold into the foot. Once the stitching has started, the curl of the foot will continue to fold the seam allowance under and stitch it in place.
- Your finished seam is beautifully finished from the front …
- … and from the back.
- Perfect every time… and no burned fingertips!
Check with your local, authorized Janome America Dealer for more information.
Our thanks to S4H seamstress team member, Michele Mishler for her work on both the testing of the foot as well as the construction of the finished sample.
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What size needle is recommended for flat felled seams ?
Hi Robyn – there isn’t one set size as it depends on the fabric you’re working with for your project. If you use something heavier, like a denim, you’d likely want a Jeans needle at maybe a 90/14. For a quilting cotton, your standard 80/12 universal needle would be fine. If you are adding a flat felled seam to a fine fabric, you might go to a 70/10 or even a 60/8. Here’s an article we did on needles that might help: https://sew4home.com/choose-the-right-sewing-machine-needle-for-your-project/
I like to use flat felled seams on shirts and blouses. If I wear a blouse unbuttoned over a tank top the inside of the blouse is nicely finished. I have a serger but the flat fell finish is worth the extra time.
Great point, Janice – when things look good both inside and out there are so many options 🙂
My sewing machine only goes to 7mm. Is there a similar foot for this width?
Hi Lori – We haven’t heard from Janome about an option for the 5mm or 7mm models, but will certainly let you know if/when we do.
Sounds awesome. My machine is a Janome 6500, will this foot work on it?
Hello Linda – this foot is made for machines with a 9mm stitch width. The 6500P has a 7mm max, so this foot wouldn’t work. As mentioned in my reply above, we haven’t heard about an option for the 5mm or 7mm models, but will certainly let you know if/when we do.