Can 4-Way Stretch Eliminate the Need for an FBA?

I’ve been thinking about this for a while. I got an email one time, telling me that 4-way stretch knits (that is, knits that have equal stretch in both their length and width) are recommended for many tops because they allow for “busty ladies” to wear them.

That logic never really sat well with me. Certainly 4-way knits have a lot of stretch, and they move well, but for fit, don’t you think you would still need to do a Full Bust Adjustment (FBA)?  I’ve been too busy to test it out until today. Plus, I don’t keep a lot of 4-way knits around. But I had some Milliskin left over from Tatiana’s skirts, so I decided to put that theory to the test. I whipped up one of my favorite tops, which I have made before, and I skipped the FBA, letting the fabric do the work. Please pardon the crappy cell phone pictures. We lost power in Irene, so I’m at the studio without my good camera, and I don’t have patience to take 50 shots to get one good one. Here’s a picture of it on me, pulled down after I had just put it on.

When I first put it on, it looks okay over the bust

Now here it is after wearing it for just a few minutes. I wasn’t doing anything super extend-wise. I just walked around the studio and put some things away.

After movement, not so much...

Again, I apologize for the lousy phone picture, but you can see some telling differences. First, look at the horizontal crease above the bust at my right side. The fabric has pulled up to give more room to the bust. Also, note that the lines from the gathers are pointing more towards the sides in this picture than they are in the first picture. Again, the fabric, even though it stretches in all directions, is adjusting itself to accomodate a large bust.

The problem is that, even with a very stretchy fabric, there isn’t enough room without an FBA for the garment to fall the way it was designed. Fabric is notoriously lazy. It will move around to alleviate strain, even if it has the elasticity and tensile strength to do otherwise. An FBA would mitigate all of these symptoms, and give a more flattering fit with less tugging.

Sorry to be the bearer of bad news, but yes, you do need an FBA, even if you are working with 4-way knits. 4-way knits are great for leotards, swimsuits, and regular old street-wear, but they don’t take away all the fitting issues.

Happy sewing!

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14 thoughts on “Can 4-Way Stretch Eliminate the Need for an FBA?”

  1. I think it’s really neat that you put that theory to the test. Good demonstration! Thanks for sharing.

    Good luck with the storm and its aftermath. It’s not fun to be without power for extended periods of time.

  2. I’m so glad to see this. It looks like one of my favorite patterns, too. (A Jalie?) I’m new to FBA’s and stumped with how to do one on something with gathering at the neckline. (I’m afraid of fouling up the shape.) If you don’t mind sharing, how do you do an FBA on this pattern? (I’m not happy with just grading out to a larger size at the armhole.)

  3. Thanks for this demo! I’ve wondered this myself and although I don’t consider myself to have a full bust, I have a dress that looks like your 2nd picture…time to learn a new skill 🙂

    Glad to hear you survived Irene.

  4. That’s great that you tried it out. If you had taken a poll beforehand, I would have predicted that the FBA is needed. Statements like that are generally not coming from folks with real bust issues, at least in my experience. 😉

  5. This is a must needed post. I have experienced exactly what you demonstrated here. The horizontal lines and/or the pulling/tugging is not pretty. We certainly don’t need to fight with our clothes. I’m sold; do a FBA even if the fabric has 4 way stretch.

    Thanks again, Ann.

  6. Thanks !

    I learned this while shopping not long ago. Having lost some weight, my body fits size Small in a lot of cases. I’m not large busted but bigger than a Small fits. I tried on a very drapey V-neck tee that had gathers at the bottom of the V. In the Small, the gathers pulled out over the bust even though it fit everywhere else, in the Med, they draped down like they were supposed to.

    I’m learning to carry this type of info over to my sewing 🙂 guess I always have to do an FBA.

  7. Cool demo – thanks Ann! but yes i suspected as much! After several attempts @ mainly Vogue patterns which my top half really swam around in, regardless of stretch or no, I figured out to go by my high bust measurement and taught myself how to do a FBA- voila! Much better fit! @Sharyn – it doesn’t matter if the pattern has gathers at the neckline, since the adjustment is sourced from the shoulder seam and the side seam. I am by no means a sewing maven and I’ve read lots of different instructions on “how to do a FBA”, NONE of which ever made any sense whatsoever. But Sew Today magazine did a really good article by Kathryn Brenne a couple of years ago which covered, in easy to follow steps, the general principles, adding a dart to a general bodice pattern, altering an already darted bodice, and altering a princess seam pattern. Yay! I’m sorry I can’t remember which issue it was. Following those guidelines I recently managed to successfully alter a raglan sleeve pattern Simplicity 2846- cute!) too – I always need to lower the bust point and do a wider spread between bust points and do a C-cup adjustment. Easy peasy! Good luck – and heavens – don’t just grade the pattern out at the armhole or you’ll be swimming around! Happy sewing 🙂

    1. Hi Paula. Thank you! I have no idea why I thought fabric would somehow be added along the shape of the neckline (bad RTW examples?) but your remarks point me toward logic and common sense which I swear (embarrassingly so) eluded me before. (It was either a case of “FBA information overload” or the fear of altering – but I’m going to take a stab at FBA with this particular style pattern and this time go at it with (a bit of )confidence.


  8. As a 10FF, I have puzzled on this for a while and tried several methods for FBAs in knits (2 and 4 way). Generally I add extra length to the front and ease it into the back. However, this seems to work better for patterns designed for 2way knits. The proportions of 4 way knit patterns often seem a lot shorter and this method is not as successful. The properties of 4 way knits work best with very tight clothes (active wear, swimsuits) which are ‘held down’ by the body – but you don’t necessarily want everyday clothes to be that tight!
    I would be interested to know your method for FBAs in both 2 and 4 way knits.

  9. Thanks for the experiment, and the NOT crappy photos. I wonder if “FBA not needed with 4-way stretch fabric” got started because it might be true for leotards, bodysuits, tops that are held down some way (tucking in, waist tie, etc.) or for up to a certain cup size, and somewhere along the line, that last part got left off or not heard.

    “Fabric is lazy” – I’ll have to keep that in mind next time I’m tempted to take a shortcut in fitting a pattern.

  10. I was wondering which pattern you are using here. I’m a 34G, and definitely need to make the FBA’s. I have looked at many explanations and will admit, I really haven’t had the nerve to try (which is rediculous since I’m 50 and have sewn since my teens). You may have given me the nerve to try again. Like most posters here, I would love to know if there is an easy, ‘foolproof ‘, method.
    Just found your blog and love it! Good job.

  11. This just happened to me making the sleeveless version of Vogue 8669 in silk jersey. I’m going to attempt to save the top by taking it apart and adding a gusset to add more room for the bust. I’m curious how you would do a FBA for your top pictured above?

    1. I am just beginning to try FBA’s and I use the following as my guide. It seems to be the clearest explanation I’ve found. If anyone has a better explanation, please share!

      Since I’m a G, it seems I add a lot of fabric. Haven’t really gotten an adjustment I truly like, but I can tell I’m on the right track. I just have a hard time knowing where to move the bust darts! And getting the proper dart ‘height’ (how much to add on the seam side).

      I also found an explanation at It’s related to a specific pattern, but seems to give some detailed explanation for those of us who aren’t confident of the FBA.

      Thanks for the pattern number. Seems a very nice blouse to put under sweaters and jackets.

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