Not sure whether you need to make an SBA? You might like to have a read of our Measuring and Cutting post from earlier this week, where we discuss taking your high bust measurement. Once you've got your high bust measurement, if you're answering yes to any of the below, it's likely you'll need to make an SBA:
- Your bust measures less than 2" larger than your high bust
- Your bust measurement falls into a smaller size than your waist measurement
- RTW clothes gape or are too loose around the bust
- You are an A/B cup
Start by making a toile (or muslin), using the size that best corresponds with your waist measurement. It's important to insert an invisible zip into the centre back seam so you can fasten up the toile properly (but make sure it's long enough so that you can get it on and off!).
Making a Small Bust Adjustment for Princess Seams
This is a fairly easy adjustment to make which basically just requires you shortening the pattern across the bust, as you don’t need as much fabric to cover the length of your torso.
1. Try on your toile and mark your bust apex directly onto it (which is usually where your nipples are!) using a felt tip. The mark should straddle both front and side panels.
To figure out how much you need to take out, simply pinch out the excess fabric horizontally across the front of your toile, keeping in line with the apex of your bust as shown in the above picture. Pin this tuck of fabric, which should taper off towards the side seam.
2. To measure how much fabric you’ll need to remove, take your toile off and mark where the pins are either side of the fold along the princess seam. Unpin and measure between the markings. If you prefer, you can also measure the fold and double this measurement, to account for the two layers of fabric. In this example we need to take out a total of 1cm of length from the front bodice pieces.
3. Transfer the bust apex marking from your toile onto the pattern pieces.
4. On the centre front, draw a line through the bust apex, perpendicular to the grainline. On the side front, draw a line through the apex to the side seam at a slight angle, as if drawing in a bust dart.
5. At 1.5cm from the edge, draw a small section of the seam line on the side seam of the side front as shown above.
From the princess seam edge, cut along the horizontal line stopping just at the seam line marking. (In order for the front and back bodices to match when you're sewing, we don't want to shorten the side seam here, so make sure you don't snip into the seam allowance.)
6. On the side front, fold the pattern so it overlaps by the adjustment amount (in our case 1cm). Before you fold, it can be helpful to draw in the seam line here (1.5cm from the princess seam edge), as the overlap needs to take place on the seam line rather than the cutting line. Tape this in place.
7. On the centre front piece, cut all the way across the pattern on the line you drew. Overlap these two pieces by the adjustment amount and tape in place.
8. Smooth out the curve of both pattern pieces if necessary, and make sure to re-draw in the grain lines as shown below.
And there you have it! Your Small Bust Adjustment for princess seams is complete!
Now you can cut out your fabric ready to sew.