Stabilizing seams. Admittedly, it’s not a sexy topic, but it’s something all sewists have to keep in mind as they construct long-lasting garments.
Let’s chat about why you should stabilize seams, which seams need extra strength, and the pros and cons of your seam-stabilizing options.
Why Bother Stabilizing Seams?
Stabilizing seams keeps a garment from stretching out before its time, and this reinforcement is especially important for knit garments.
Woven fabrics have built-in stability, thanks to warp (vertical) and weft (horizontal) threads. Unless you pull on the bias (diagonal) of a woven fabric or it has some spandex in the fiber content, it won’t stretch (much).
Knit fabric, to compare, is composed of rows of looped threads, which have more give. Even a knit fabric without spandex fiber will stretch (to some degree) because of the loop structure. Knits can’t help but stretch, hence the need for stabilized seams.
It’s also good to stabilize seams when bigger pattern pieces come together (e.g., waistband). Stabilizing seams is all about adding strength. 🏋️♀️💪🏋️♂️
Which Seams Should I Stabilize?
Here’s a rundown of which seams should be stabilized (especially in knits):
- Shoulders: Gravity works against shoulder seams to stretch them out.
- Armholes: The curved shape guarantees stretch from the bias.
- Bias seams: Bias = stretch (obviously).
- Off-grain seams: When you get seams off grain, they’re less strong and more stretchy.
- Waistlines: Big seams needs big strength.
- Curved necklines: Bias at issue (again).
- Pocket openings: Stabilizer adds strength to this stress point.
- Gathered seams: Additional bulk could use additional strength.
Word of warning: If you have a garment with a lot of negative ease, be careful about what you use for seam stabilizer and where you employ it. Negative ease works because of stretch, so make sure you don’t do anything to compromise that.
You definitely can understabilize a garment, but I think it’s almost impossible to OVERstabilize one.
How to Insert Shoulder Stabilizer
In my experience, the most common seam to stabilize is the shoulder seam. I always stabilize the shoulders of my knit me-mades.
(Yes, I’m talking about shoulder seams here, but you could apply this technique/insight to any seam that needs to be stabilized. You feel me.)
Here are my seam-stabilizing steps for shoulders:
- Cut a piece of stabilizer that’s LONGER (1-2 inches) than the seam.
- Place front and back bodice pieces together, right sides facing.
- Place the two pieces of aligned fabric under your presser foot.
- Place the stabilizer atop the two bodice pieces at the intended seam line, with excess length (maybe ½ inch) behind the presser foot.
- Sew/serge down the middle of the stabilizer to the end of the seam.
- Trim excess stabilizer from both ends of the seam.
Pro tip, part 1: Think about the direction in which the seam will pressed, and try to keep the stabilizer away from your skin, if possible. You’ll be more comfortable. For shoulders, this usually means sewing/serging the stabilizer with the BACK bodice on top (FRONT bodice against the throat plate). I like have the stabilizer on my back vs. my front shoulders.
Pro tip, part 2: With some sergers, the basic serger foot has a slot for stabilizer. The slot on my Babylock Imagine serger foot is about ¼ inch wide, and it perfectly accommodates ¼ twill tape (my fave stabilizer). I slide twill tape through the slot, make sure a bit of it is pulled out under the back of the presser foot. Then I put my two layers to be serged under the presser foot and start serging at the correct seam allowance. It’s pretty slick, IMO.
Seam Stabilizing Products
Twill tape is my favorite seam stabilizer. I like preshrunk cotton twill tape because its soft and a natural fiber. Twill tape looks like a ribbon, with its stretch-adverse herringbone weave. (BTW, if you’re so inclined, you also can use skinny ribbon for stabilizer. Test it to see if you like it!)
Related to twill tape (sort of) is selvage. Selvage is strong, and it’s a good way to upcycle fabric.
Pro: It’s soft on the skin.
Con: Twill tape is mildly bulky and not good for seams with negative ease. Twill tape doesn’t really stretch; that’s why it’s great for shoulders.
Sewing directions often call for clear elastic as a shoulder stabilizer. It pairs particularly well with lightweight knits.
Pro: It’s lightweight. It’s also good for garments with a lot of stretch and garments with negative ease.
Con: It’s easy to overstretch elastic whenever you sew with it. Learning curve could be frustrating.
Interfacing is all about additional strength, right? Right. Press interfacing on the vulnerable seam area before stitching it.
Pro: This is a good way to use up those random interfacing scraps!
Con: Could be bulky or difficult for the needle to create nice stitches. May need to trim down width before stitching.
Woven Fabric Cut on the Bias
Strips of woven fabric cut on the bias are stretchy and a surprisingly good match for knit fabric. (I finished a knit shirt with woven bias tape.)
Pro: You can put small pieces of woven fabric to use as bias tape.
Con: I don’t know about you, but even though I love using homemade bias tape, I hate making it because the process is futzy.
There are different kinds of stay tape. There’s a Dritz non-adhesive nylon tape (above), and a fusible style of stay tape. Both kinds do the same thing — keep seams from stretching.
Pro: Stay tape is lightweight.
Con: The nylon stay tape stabilizer itches my skin.
In the end, I think you’ve got to test a few different kinds of stabilizer to discover which types work best for various garments and which ones you most enjoy working with. Test and test again!
If you’ve got questions about what stabilizer is going to work for your project, post your query to “sewcial” media — Facebook groups, Instagram, PatternReview.com, fave blogger/vlogger/podcaster, etc. Search IG for the project hashtag and hit up other sewists who’ve made the same garment for insight. We’re a friendly bunch who want to help!
Heck, ASK ME!!! (It’s hard, as a modest, Catholic Midwesterner, to put myself out there as somewhat of an expert! I feel so weird, guys.) I’m not claiming to possess all sewing knowledge, but I could be a good jumping off point. Try me.
Other to you, sewing friends: What’s your favorite notion for stabilizing seams? Which seams to you stabilize on the regular? Please share in comments! Thanks, and thanks for reading.
P.S. Here’s the previous post, ICYMI: The Boundless Style Maxi Dress: Lady in Red.
Photo by Victor Freitas on Unsplash
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