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Rounded back adjustment without centre back seam or shoulder dart

I was sewing a toile for my Freya Dress which is a knit dress with a fitted bodice. I had drag lines down the back indicating I needed a rounded back adjustment or RBA (see this post for my entire fitting process and photos of my toile). Once I cut across the back, the fabric spread apart indicated more room was needed here.

Back view of toile of Tilly and the Buttons Freya Dress showing slashed fabric at the upper back with it spreading apart

In this pattern, the back piece is cut on the fold. RBAs generally require a centre back seam or a neck/shoulder dart but I didn't want either, plus I didn't want to change the neckline or armhole length. I thought that with a knit I might be able to get away with some creative pattern work.

The tutorial below shows my adjustment for 3cm but after trying another toile, I realised I needed more and so my final adjustment was for 5cm. The Palmer/Pletsch book recommends a maximum upper RBA of 1.5cm at the neckline seam and any further adjustment to be made as a lower RBA between the armholes.

In the photo below, the black dotted line is a line drawn between the neckline and hem, and shows the curve that the RBA has added to the fold line. My first thought was maybe just to cut this off to make it straight again, but this would have reduced width. Having measured across to the armhole and comparing to a RTW top I have, I needed the full width and so this is a post describing what I did. With this being a knit top, it was hard for me to know if this actually worked and I'm sure I can hear some horrified gasps from those experienced in fitting! However, it seemed like it made sense to me so here goes:

Step 1 - Place pattern on a grid with neckline seam and hem touching the line

Pick any line on your grid and place the pattern on it so the top and bottom of the pattern piece line up with it. The RBAs will cross this line.

Back pattern piece of Tilly and the Buttons Freya dress showing upper and lower rounded back adjustments

Step 2 - Add extra pattern paper for adjustments

Place some extra paper under the top part of the bodice or trace the full pattern piece onto another piece of paper but don't trim it yet. Mark where the neckline starts.

Back pattern piece of Tilly and the Buttons Freya dress showing upper and lower rounded back adjustments, showing pivot point to avoid shoulder dart or centre back seam

Step 3 - Pivot pattern at the neckline

Pivot the pattern around the neckline point until the top part of the pattern (indicated by the white line) sits on the line.

Step 4 - Draw around the pattern piece to the armhole hinge

Draw round the pattern until you get to the armhole hinge where the lower round back adjustment was made (between the 2 arrows)

Step 5 - Pivot at the armhole

Pivot the pattern at this armhole hinge until the bottom part of the pattern (white line down to the hem) sits on the line again.

Step 6 - Draw round remainder of armhole

Draw round the bottom part of the armhole, between the two arrows.

Step 7 - Attach additional paper to the pattern piece and trim along the line

Tape the additional paper to the pattern, lining up your starting point mark at the neckline and the bottom of the armhole with the original pattern. Trim the pattern along this line. (Sorry, forgot to take a photo at this point)

Step 8 - Trim the fold line straight between the neckline and hem.

Cut the back centre fold line straight between neckline and hem. This means that the centre back line is now straight with extra length for the rounded back, but the width of the back isn't reduced and the neckline and armhole length remain the same.

Finished back pattern piece for Tilly and the Buttons Freya Dress with upper and lower rounded back adjustments without a centre back seam or neck or shoulder dart

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Palmer/Pletsch book: Complete Guide to Fitting

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I'm Kay, and welcome to my blog where I share tales of my sewing journey, complete with mishaps, mistakes and solutions to help make your journey a smoother one.

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