May 20, 2014

Sewing Indie Month: 2 FBA approaches

I don’t know about you, but in the summer, my wardrobe is veritably overflowing with tops. Tops, shorts and colourful jeans – which I have yet to learn how to make… Must try soon!

Anyhow, the big challenge with a lot of casual top patterns is that many of them are drafted for a B or C cup (with a few notable exceptions – BlueGingerDoll for instance is drafted for a D). For some people, that means they end up cutting the size to fit their bust but the rest of the top swamps them. For others like me (my 46″ bust scoffs in envy at your C cup), we’re totally sized out of most patterns.

But fear not! The Full Bust Adjustment (FBA) was invented by some busty genius to solve all your problems. And contrary to internet rumour, it really isn’t very difficult at all. There are a few different techniques, but today I want to share with you my favourite approach for wovens, and for knits

The Cashmerette Tried & Tested FBA for Wovens 
I’m with the Fit for Real People faction, all the way. Their approaches are easy, and pretty much foolproof.

These methods work well for patterns like:

Clockwise from left:  Sew Caroline Tank DressSinbad & Sailor Dove TSkinny Bitch Curvy Chick Lemon Drop Dress

1) Darted top approach

Here are the step by step instructions for a darted top, using the Dove T from Sinbad & Sailor as the pattern:

1. Figure out how much width you need to do for the FBA. Easiest way: measure your full bust, and see how much bigger that is than the size you’re going to use. Divide that by 2 (because the pattern is half the front), and that’s how much width you need to add! Alternative method: measure your high bust (under your arms and over the top of your bust), use that size from the pattern, and add the difference between that and your full bust.

2. Mark in the dart on the pattern. Sinbad & Sailor indicate this through notches and a circle, so just join them up!

3. Mark three more lines: through the middle of the dart, from the end of the dart to the armhole (about 1/3 of the way up), and from the end of the dart vertically down.

4. Cut up the vertical line, and over to the armhole, stopping just before the seam allowance. Then, cut the seam allowance from the armhole side, leaving a little hinge (not the end of the world if you accidentally snip through!)

5. Cut through the line in the dart, again stopping just before the end to leave a hinge. Then tape down the left hand side of the pattern and “spread” the right hand side to add the width you need down the vertical gap. Keep that gap parallel all the way down! You’ll see that the dart “opens up”

6. You’ll find the right hand side is a smidgen longer than the left now, so cut a horizontal line through the lefthand side (anywhere) and slide the bottom bit down until the hem is parallel. 

7. Trace it off, and voila, you have an adjusted pattern!

2) No darts top approach

Head over here to see my full tutorial on how to add darts, and do an FBA, using the Sew Caroline Tank Dress pattern.

3) Princess seamed top approach

Here I am going to send you to my fellow 46″ buster, Mary at IdleFancy who has put together a fabulous tutorial (which is particularly good for D+ busts), using the By Hand London Elisalex bodice.

4) Troubleshooting

The only potential danger of these approaches is that it does add width throughout the length of the garment, which can particularly be a problem for dresses or longer tops.

There are a few solutions:

– For a darted top, you can add a waist dart or fisheye dart to take the excess out from under your bust. The easiest way to do this is to pin out the excess when you’re wearing the top, and then transfer that into a dart. This is what I did with my Archer shirt, and it worked well.

– For a princess seamed top, before you do the FBA, cut off the top piece of your pattern at about an inch below your bust level. Do the FBA on the top part, then stick it back to the bottom piece and grade from the one size to the other. This is what I did on my coat, and again it worked perfectly, giving me extra room in the bust but tapering back in underneath

The Cashmerette Tried & Tested FBA for Knits 

So the good news is that most of the time you don’t need to FBA knits due to the JOY OF STRETCH. However. Sometimes two things happen when you’re relying on stretch: the cat whisker wrinkles emanating from the armpits (busty ladies, you know what I mean, right?), and/or the front hem is significantly higher than the back hem because your chest is lifting it up.

But fear not! Because doing an FBA for knits is actually much easier than doing it for wovens, and it’s worth it for getting the perfect fit. The approach I use is the “vertical only” FBA, which has been covered in a few places before including by Skinny Bitch Curvy Chick and by Shams at Communing with Fabric (who has a wealth of other knowledge on FBAs, so check her out!).

This approach works for patterns like:

Clockwise from left: Tilly’s Coco Top,  Skinny Bitch Curvy Chick Tonic TeeMaria Denmark Birgitte Basic Tee

Basically, we’re going to just add extra length to the front to give us more material to go over our busts, and end up with an even hem.

1. Figure out how much length you need to add. Ideally you make up a muslin and see how much higher your front hem is sitting than your back. Me? I just add an inch. What can I say, I’m a rebel.

2. Cut through your piece at bust apex level

3. Move the  bottom piece down the requisite length – here I added an inch to my Renfrew:

4. Curve out the side seam slightly to add a tiny bit of width (I added about 1/8 inch)

5. Now here’s the important bit. The front and back are now different lengths. When you come to sew them up, pin at the armscye and hem. Start sewing the seam at the bottom hem and work up the armscye. Then, about 4 – 5 inches below the armscye, start easing the front piece into the back piece (for newbies: this means start stretching the shorter layer so that it is the same length as the longer layer, holding it taut while it goes through the sewing machine/serger). By the time you reach the armscye the pieces should be matching.

Et voila! The only downside to this approach is you can’t do stripe matching under your arms, but I suspect there’s more to life than perfect stripe matching (no?).

OK, well I hope this has been helpful! Have you run into any FBA woes readers? I’m happy to consult!

You can enter the Sew Indie Month everyday casual contest by submitting a link to your blog, Pattern Review or Kollabora on this page.

14 thoughts on “Sewing Indie Month: 2 FBA approaches

  1. When you’re doing an FBA on a darted pattern do you redraw the V of the dart so the the legs on the side seem are the same distance apart as they were originally, or do you leave it however wide it is after you spread it? Does that make sense? I’ve only done an FBA on one pattern so far & I left it however wide it was after spreading. When I tried the top on everything fit except it pulled funny in the arm hole across my upper bust. The full bust area was fine though. I’m not sure if I also needed a shoulder adjustment or if I did the darts wrong. I was making Colette’s Laurel if that helps.

  2. Jenny says:

    Hi Melissa
    Good question! You have added more to the dart in the FBA so you keep the original dart lines, that are now further apart. That wrinkle at the armhole is quite common if you do a big FBA. Two fixes are to do another short dart at the armhole (this is what I did on the Sorbetto), or you can reshape the armhole on the pattern piece – the FBA can distort it if it’s big, so you can use a French curve to re-do it. Often the easiest way to figure out what to do is just try the garment on and “pin out” the excess – then you can decide if another dart will work or if you need to reshape the armhole

  3. Thank you SOOOO much!!! I was following both Gertie’s book & the Colette Handbook & neither one made this part clear enough to me. Good to know I did it right, I just needed to adjust my arm hole. 🙂

  4. Karina says:

    I’ve been having so much trouble with doing the FBA on the Eucalypt tank! I followed your tutorial for a dartless top and I don’t know where I went wrong. I used the measurement per my high bust 37″ and cut a M (38″) I needed to add 2.5 inches to get to 39.5″. I think I decided to try with just 2″ but now that I think of it it I did not divide it by 2. The result was so tight across my high bust it was not comfortable. Would this be because I put the full amount? The other thing is getting the dart placement, the fabric I’m using is very slippery and drapey and I can’t figure out if the dart should be fitted or not.

    1. Jenny says:

      Hmm that is curious! It depends a little on where the fullness of your bust is, but this is the joy of muslins – you can try it again until it’s perfect and then you can make the top again and again! Moving a dart up or down is easy – just draw a box around the dart on the pattern, cut it out, move up or down as needed, and then smooth out the side seams . For the high bust approach you are meant to add the difference between your high bust and full bust – is that what you did? To be honest the high bust approach doesn’t work for me so the alternative is to measure your full bust and pick the closest size and add whatever you need.

  5. Karina says:

    Thanks Jenny! That’s great idea regarding the darts, will definitely try that technique instead of redoing a block every time. I did add the difference between the high bust and full bust. This is my second go at the Eucalypt top and the first time I cut a size L which is only .5″ larger than my full bust but what happens is a gap at the armholes to the high bust. Maybe its not an FBA I need to do but a slopping shoulder adjustment. Knowing which adjustment to do is so tricky sometimes

  6. Tami says:

    Is there a way of working out how many inches to add to the length, other than making a rough up garment first? I’m wondering if there’s a chart with bust size by # of inches that could give me a rough guestimate start.

  7. Holly says:

    Jenny, The Bust now fits perfectly but the 4 inches added to a swing top now make in look like a preggy shirt. Do you think I can just grade 4 inches after the bust to the bottom?I think I have too much swing!

    1. SingleMom56 says:


  8. SingleMom56 says:

    great information, but does not help when you don’t need extra width to a garment at the side seams. room for the bust, but then way too much width in the waistline area. what then? more info please. how do you make a FBA into a fitted garment thru the waist and back after adding extra bust????

    1. For extensive help on this question, and all types of FBAs, check out my class on BluPrint:

Let me know what you think!