Kim Dress Sewalong - Alterations - Full Bust Adjustment for princess seams (FBA)

Aloha Sewists, and welcome to the Alterations section of the Kim Dress Sewalong! Throughout these posts we will be going through as many pattern alteration tutorials as we can physically crush in, relevant to the Kim Dress. But it doesn't end there - the extra great news is that a lot of these tutorials will be applicable not only to the Kim, but to a huge amount of other patterns too as we tackle most of the common issues surrounding pattern fitting. 

*To be taken to all the posts in the Kim Dress Sewalong, please click here!*

We've eased you in gently with some simple bodice alterations so far, but today I'm turning up the heat! Unlike needing to alter the length of a bodice, or fix an unruly neckline - which can only be diagnosed from an ill-fitting toile, you probably knew that you needed to make a bust adjustment the moment you took your measurements. Before we begin, let me ease your mind by saying that full bust and small bust adjustments aren't difficult - they're just a little long-winded. However, once you've done it, the whole process will make total sense, and when you try your newly adjusted toile on, you'll see what a world of difference a well-fitting bodice makes!

What you'll need:

  • Your traced bodice front pieces of the Kim Dress (Variation 1 or 2, cut out in the size dictated by your waistline measurement)
  • Paper scissors (not the fabric shears!)
  • Extra paper
  • Tape
  • A pen

Please note: We are using itty bitty replica's of the pattern pieces to illustrate the alterations as simply and clearly as possible - please make sure that you alter your real-life pattern pieces, complete with notches, pattern info and grainlines!

How do I know if an FBA is in order?

Step 1

We need to begin by taking the bodice centre front and bodice side front pieces and marking out the seam allowance lines at the side front seam, the underarm seam and the side seam (shown in blue).

We also need to mark the apex (shown in pink) - this is basically the fullest part of the bust, or the nipple point.

Step 2

We now need to mark a series of slash lines along key points of the bodice side front - it is along these lines that we're going to cut and open it all up to create some more space for our ample bosoms!

The first line goes from the apex and down to the waistline, skimming the seam allowance line.

Step 3

Draw a second line from the apex and up to the armhole, quite high up - just before the armhole curve starts is ideal. In order to be able to open up the bust to create space without chopping up the bodice completely, we need to factor in some pivot points, or hinges. The first pivot point is marked by a little circle at the seam allowance line at the armhole. When we come to cutting along this line, we'll cut right up to the circle, and then we'll snip in to the circle from the seam allowance.

Step 4

The third line we need to mark goes from the side seam - a couple of inches down from the underarm - and up to the apex. Where this line meets the apex will also be a pivot point.

Step 5

Aaaaand the final line is a small horizontal line going from the first line we drew out to the side front seam edge.

Step 6 

Now comes the fun - but also quite fiddly! - part: slashing.

Cut line 1 from the waistline up to the apex and continuing along line 2 until you get to the armhole pivot point. 

Snip the seam allowance at the armhole to meet the pivot.

Cut along line 3 from the side seam, stopping just shy of the apex, allowing this point to pivot also.

You should be able to see now how we can open the bodice up to create more space, or close it in on itself to reduce volume.

Step 7

Take your bodice side front and place it onto a piece of scrap paper. Tape down the strap part of the bodice to secure it.

Step 8

We're now going to spread the pattern out according to how much we need to increase the bust measurement by.

For example, your bust measurement is 37" putting you in the size UK14 bracket, but your waist measurement is 28" putting you in the size UK12 bracket, and you have therefore cut out a size UK12 bodice. Seeing as your bust is 2" larger than the size UK12 bust of 35", you'll need to open up each side of your bodice by 1", totalling 2" extra inches all round. Remember, you only need to open up your bodice pattern piece by half of the total amount you need to increase the bust by, as once it's all cut out you'll have two!

Open up the pattern piece and measure your 1" (or however much you're increasing your bust by) across the split line 1:

Step 9 

When you're happy, tape it down.

You'll see that the right hand portion of the bodice is now significantly longer than the left hand slither - fix this by snipping line 4 and bringing it down to match the waistline, keeping the side front seam line flush.

Step 10

Now that we've created more width across the bust, we need to close up the massive side dart we've ended up with!

Using the image below as a guide, draw a straight line along the bottom part of line 3, continuing through the apex and out of the side front seam edge.

Cut from the side seam along this new line (let's call him "red line"), stopping at the apex.

Now cut along the red line from the side front seam towards the apex, but not through it - we need to keep the apex as a pivot point!

You'll see that you can now hinge the bodice, allowing you to close that side dart, bringing line 3 back together, and thereby opening up the curve at the bust.

Slip another little piece of scrap paper underneath this opening at the bust, tape it down and redraw the bust curve. In doing this, we've now increased the width at the bust and made that curved side front bust seam a little longer and bustier, without affecting the side seam.

Step 11

We have, however, increased the width at the waistline, which is exactly what we do not want!

This is easily amended by measuring the amount by which we've increased the waistline by...

And transferring that increase in from the side seam. You'll see the new side seam line drawn in red below, and to that you just then need to add on the 5/8" or 15mm seam allowance. 

Cut out your freshly altered bodice side front piece, and you should have something a little like this!

Step 12

Now that we've altered the bodice side front, we need to make just a couple of alterations to the bodice centre front piece to ensure that the two match when we come to sewing them up.

We need to transfer the extra length that we've added to the side front bust seam to the corresponding seam at the centre front - simply draw two horizontal lines across the centre front piece that mimic the two openings at the bust curve and further down towards the waistline:

Cut across these lines and open them up by the same amount as on the bodice side front, making sure that the centre front line remains straight.

Slip some scrap paper behind, tape it all down and cut it out.

Phew!! I hope this hasn't completely boggled your mind... Mine's feeling just a tad frazzled after writing this post! It's honestly not a complicated process, nor one that requires much brain power, just a bit fiddly and time consuming. So so worth it though!

Tip from the top: Always check your adjustment by making another toile to check the fit. Once you're happy with your newly adjusted pattern, copy it out onto some card for extra safe keeping! Although this is a straightforward adjustment to make, no one wants to have to do it twice...

  • Elisalex de Castro Peake
  • Kim DressKim Dress Sewalongpattern alterationSewalongtutorial

Comments on this post ( 4 )

  • Jun 21, 2016

    Hi Olivia,

    Yes, I think in this scenario I would cut the bodice according to your bust measurement and grade to the smaller size at the waist, and then cut the skirt in the size according to your waist so it matches the graded waistline of your bodice. Definitely make a toile first to check that you’re happy with your alterations! Hope this helps!

    — Elisalex - By Hand London

  • Jun 16, 2016

    Hi! I’m pretty new to sewing and have a question about the bust adjustment. My bust measurement is one size higher than my waist and hip size, but my upper bust is only 2" smaller than my full bust. What is the appropriate adjustment? Not sure if I should cut the smaller size and do an FBA or just grade up a size at the bust? I didn’t see any mention of grading up for the bust so wasn’t sure if this was the right thing to do.

    — Olivia

  • Aug 26, 2015

    Fantastic explaination and demonstration. I think I finally understand the cut and pivot methods. Can’t wait to give it a try. Thanks so much!

    — cindy

  • Feb 19, 2015

    Hi, not related to his post but will you be including how to add a lining to the variation 2? Now that I’ve started working with it my fabric is very thin and will definitely need to be lined. Thanks.

    — Joanne

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