Arrow Fat Left Icon Arrow Fat Right Icon Arrow Right Icon Cart Icon Close Circle Icon Expand Arrows Icon Facebook Icon Instagram Icon Pinterest Icon Twitter Icon translation missing: en.general.icons.vimeo Icon Youtube Icon Hamburger Icon Information Icon Down Arrow Icon Mail Icon Mini Cart Icon Person Icon Ruler Icon Search Icon Shirt Icon Triangle Icon Bag Icon Play Video
Jenna Dress Sewalong - Bust adjustments (FBA, SBA, moving darts)

This week we're all about nailing the fit of our Jenna dresses! Just as shop bought clothes have been drafted and produced to a "standard" chart of proportions, so too are sewing patterns. Very few people will fit a pattern perfectly right out of the box, so we find it helpful to think of sewing patterns as a foundation for limitless possibilities - not only in terms of the design, but crucially in terms of the fit.

*To be taken to all the posts in the Jenna Dress sewalong, please click here*

We're diving right into bust adjustments to begin with, as this is where most bodice issues will likely come up for this pattern. Being an Empire line dress - meaning that the waistline seam sits just below the bust and the skirt skims over the natural waist, tummy and hips - getting the right fit across the bust will have a huge impact on the way the rest of the dress falls.

Full bust adjustment (FBA)

So how do I know if I need a Full Bust Adjustment?

There are a number of ways to determine whether or not you'll need to alter your bodice pattern, and by how much. The first thing to be asking yourself (and you probably already have if you're taking the time to read this post!) is how do your clothes - homemade or shop-bought - usually fit you? Do you find that dresses and tops squish down or flatten your tatas? Or is there room for an extra padded bra or two?! If you find that you're of the former, more boobalicious variety, you've come to the right place my friend. Now let's investigate further...

Some more tell-tale signs that an FBA is in order:

  • Your high bust measurement is more than 2" less than your full bust measurement (see this post on how to measure yourself)
  • Your full bust measurement falls into a larger size group than that of your waist measurement
  • Waistlines on dresses often ride up and sit higher than your natural waist (avoid the temptation to lengthen the bodice before determining if you need an FBA first)

Step 1 

Please note that we are using itty bitty replicas of our pattern to demonstrate - it's not full scale!

We will be working on the bodice front piece A.

We need to begin by marking out the apex (which literally means the 'summit', so the fullest part of the bust - this is where the bust and waist darts would meet if extended). We also need to mark out the seam line of the armscye, 5/8" or 15mm in from the edge of the armhole.

Step 2

To do the FBA, we're going to use the 'slash & spread' alteration method. Sounds a little creepy and murderous, I know, but slashing & spreading is basically just the technique of cutting along key lines through the pattern in order to open it up to allow more space for the ladies.

Draw a vertical line through the waist dart and up to the apex (line 1).

Draw a line from the middle of the armscye (from the seam line) to the apex (line 2).

Draw a line through the centre of the bust dart to the apex (line 3).

Draw a horizontal line about an inch up from the bottom going from the red line and out to the centre front (line 4).

Step 3 

Cut upwards through line 1, through the apex and along line 2 ending at the armscye's seam line.

Snip into the seam allowance at the armhole up to the line 2, but not through it - this will be a pivot point.

Now cut along line 3 from the side seam, through the bust dart and ending just before the apex - do not cut all the way through it, we need the apex to be able to pivot.

Cut the horizontal line 4.

Step 4 - The FBA

Take your slashed bodice and place it onto a spare piece of paper. 

We are now going to open up the apex by however much we need to increase the bust by. This is the amount that the size you have cut needs to increase by to get to your full bust measurement. If you have started with a size 12 whose bust measurement is 35", but yours is 37", you will need to increase the apex by 1" to give you the 2" total extra space around the bust, as we're working on one half of the bodice front.

Spread out the bodice, pivoting at the armhole and apex. When you have opened up the apex by your desired amount, making sure that the vertical opening is even and parallel, tape it all securely down.

You'll notice that by slashing and spreading your bodice, the side seam will have become longer. Because of this, we now need to lengthen the centre front to match. Simply move the bottom left piece (where we cut horizontally along line 4) down, keeping the centre front perfectly flush. Tape into place.

The extra space that the FBA has created in the bust and waist dart will be swallowed up when they're all stitched up, so the last thing to do is redraw the darts.

For the waist dart, mark the new tip in the middle of the opening created by the FBA, at the same height as the original dart leg closest to the side seam. Reconnect this new dart tip with the notches at the waistline. Redraw the bust dart by creating a new tip in the middle of the opening at line 3 and connecting it with the original notches at the side seam.

Cut your newly altered bodice out!

No alterations need to be made to the bodice back piece to match. Now that you've done your FBA, make up a new toile to check the bust dart - it needs to be pointing directly towards your apex/fullest part of your bust. If it doesn't, you may need to lower or raise the dart - skip to the bottom of this page!

Small bust adjustment (SBA)

How do I know if I need a Small Bust Adjustment?

There are a number of ways to determine whether or not you'll need to alter your bodice pattern, and by how much. The first thing to be asking yourself (and you probably already have if you're taking the time to read this post!) is how do your clothes - homemade or shop-bought - usually fit you? Do you find that dresses and tops squish down or flatten your tatas? Or is there room for an extra padded bra or two?! If your answer is 'yes' to the latter, you've come to the right place my friend. Now let's investigate further...

Some more tell-tale signs that an SBA is in order:

  • Your high bust measurement is up to an inch less than your full bust measurement
  • Your full bust measurement falls into a smaller size group than that of your waist measurement
  • Waistlines on dresses often sag down, falling below your natural waistline (avoid the temptation to shorten the bodice before determining if you need an SBA first)

OK guys, let's do this.

Step 1 

Please note that we are using itty bitty replicas of our pattern to demonstrate - it's not full scale!

We will be working on the dress front piece A.

We need to begin by marking out the apex (which literally means the 'summit', so the fullest part of the bust - this is where the bust and waist darts would meet if extended). We also need to mark out the seam line of the armscye, 5/8" or 15mm in from the edge of the armhole.

Step 2

To do the FBA, we're going to use the 'slash & spread' alteration method. Sounds a little creepy and murderous, I know, but slashing & spreading is basically just the technique of cutting along key lines through the pattern in order to open it up to allow more space for the ladies.

Draw a vertical line through the waist dart and up to the apex (line 1).

Draw a line from the middle of the armscye (from the seam line) to the apex (line 2).

Draw a line through the centre of the bust dart to the apex (line 3).

Draw a horizontal line about an inch up from the bottom going from the red line and out to the centre front (line 4).

Step 3 

Cut upwards through line 1, through the apex and along line 2 ending at the armscye's seam line.

Snip into the seam allowance at the armhole up to the line 2, but not through it - this will be a pivot point.

Now cut along line 3 from the side seam, through the bust dart and ending just before the apex - do not cut all the way through it, we need the apex to be able to pivot.

Cut line 4.

Step 4 - The SBA

We are now going to reduce the apex by however much we need to decrease the bust by. This is the amount that the size you have cut needs to decrease by to get to your full bust measurement. If you have started with a size 12 whose bust measurement is 35", but yours is 33", you will need to decrease the apex by 1" to eliminate the 2" total unwanted excess around the bust, as we're working on one half of the bodice front.

Move the bodice in on itself, pivoting at the armhole and apex. When you have reduced the apex by your desired amount, tape it all securely down.

You'll notice that by slashing and reducing your bodice, the side seam will have become slightly shorter. Because of this, we now need to shorten the centre front to match. Simply move the bottom left piece (where we cut horizontally along line 4) up, keeping the centre front perfectly vertical and flush. Tape into place.

Now we have to re-draw the dart. Peasy!

Using a ruler, re-draw the dart legs starting at the original dart point and going out to the dart notches at the side seam. This now narrower dart will keep the side seam measurement the same as when we started. If you can't see one of the original notches, just fold the overlap out of the way.

Snip away the excess at the dart extensions and your new bodice is done!

All done! No alterations need to be made to the dress back piece to match. Now that you've done your SBA, make up a new toile to check the bust dart - it needs to be pointing directly towards your apex/fullest part of your bust. If it doesn't, you may need to lower or raise the dart - coming up right now!

How to raise or lower a bust dart (moving the apex)

Sometimes the simplest alterations we can make to a pattern are the ones that end up making a world of difference. Moving darts - especially bust darts - is one such miracle alteration.

For this tutorial, we will be demonstrating on a bust dart that starts at the side seam, as on our Jenna Dress pattern, but you can apply the exact same process to any dart that should be pointing towards the apex, or indeed any dart at all that you feel should be moved, once you have grasped the concept of moving darts in order to better direct fullness.

A dart is a long and narrow triangle shaped wedge that we sew in order to give 3D shape to a garment. Darts on a bodice are typically found coming from the side seam, waistline, underarm, and/or shoulder seam pointing towards the bust. When a dart points perfectly towards the apex (aka your nipple! Or the fullest part of your bust if that's not indicated by your nipple!), it is directing the fullness in the bodice to the fullest part of your bust, where it needs to be in order to fit well. If the dart does not point towards the bust, it will be directing fullness to a part of your body that does not need it, resulting in a squished boobie and a puckery, saggy-looking dart point. Not what we're after.

It's easy to tell if your dart is in the wrong place for you, but you will need to make a toile. This type of alteration cannot be spotted by comparing your measurements to the sizing chart.

Try on your toile, and check yourself out in the mirror. Make sure that you are wearing the same bra that you intend to wear with your finished garment! All you need to ask yourself is simply, "does the dart point directly to the fullest part of my bust?".

If the dart is pointing above your apex (which, let's face it, will be the case for most of us as our breasts tend to head south as we age / have babies / live our lives), you will need to lower the dart. Measure the distance between where the dart point is, and where it should be in order to be pointing towards your nipple. This is the amount you will need to lower your dart by.

If the dart is pointing below your apex, you will need to raise the dart. Measure the distance between where the dart point is, and where it should be in order to be pointing towards your nipple. This is the amount you will need to raise your dart by.

On your pattern paper, draw a rectangular box around your dart: 

Cut the box out.

Slip some scrap paper underneath, and, keeping the box parallel so as not to alter the angle of the dart, and the vertical cut line flush so as not to move your dart out of the bodice, move the box up or down by however much you need to raise or lower your dart. When you're happy, tape it down.

When you lower or raise a dart, you'll usually have to shorten or lengthen the waist dart accordingly.

True out the side seam ("true out" basically just means redraw the side seam so it's all smooth and nice again), and trim away any excess.

And there you have it! With all alterations, we highly recommend that you make another toile to check that you're happy with the alterations that you made before cutting into your delicious fashion fabric!

Comments on this post (0)

Leave a comment