Some of my favorite tops have a gathered side seam. I love how they add a little flair and help conceal things. My birthday is fast approaching and I have been promised an evening out so I decided I needed a gathered side seam Not So Cold Shoulder (NSCS) for the occasion. I used Ripley Double Brushed Polyester (DBP) for my top. Unfortunately Ripley is out of stock, but Amelia Lane Designs does have some other amazing DBPs available. DBP is a great option for this because it is light enough to handle the gathering well. But other lightweight fabrics with good recovery like the Jersey Moss will also work well.
Some adjustments need to be made to the pattern before you start cutting, otherwise your NSCS will end up too short. That is great if you want a shorter finished length, but if you don't you will need to add length. You will also need elastic: I used 1/4" elastic sewn into my seams to gather my lengthened bodice. Swim elastic is really soft, so it is a great option, especially if you have sensory issues. I used diaper elastic I had on hand. It isn't as soft as swim, but it is softer than most craft store options.
Cut your bodice pattern pieces along the lengthen/shorten line to add length. I used parchment paper to do this, but printer paper or tracing paper will also work well. Draw two lines parallel to each other: I added 6" for mine, which was the width of my ruler. On one side draw a straight line parallel to the your two lines. You will use this to line up your cut edges of your split pattern pieces. Tape or glue in place along your parallel lines and redraw the side curves to smooth the pattern pieces out. This is shown in the collage bellow.
Alternatively you could split one of the bodice pieces, cut around the sides and bottom, then carefully lift the pattern piece, lay your unaltered second bodice piece down, lining up the edges, and cut along the top. I chose to split each pattern piece because it never fails that I shift my fabric and end up with a mess somewhere.
Time to Sew
Cut out your pattern pieces and sew according to the tutorial, leaving the bottom un-hemmed. Now it is time for the elastic. Because every elastic is different it is better to stretch between the points you want to gather then figure out a length a different way. To do this turn your shirt inside out, set one of your bodice pattern pieces on top and place a pin on each side seam where you cut to add length. Place another pin on each side a little above where you'll turn to hem. These two points are where you'll start and stop the gathering. Before starting with your elastic it is a good idea to pre-stretch it. This is because most elastics will not recover 100% with the first stretch, but do after that.
Adding the Elastic
Mark your elastic 1/2" from the edge: this gives you length to hold while sewing. Lay the elastic along the seam, with your mark at one pin, hold in place with a wonder clip or second pin. Measure in from the other pin the extra length you added in, place that over the pin and hold in place. Stretch your elastic out, then slowly release, and compare to your pattern piece. This will help determine if the elastic needs to be shorter or longer. If you cannot stretch the elastic between those points you need to make it a little longer. If it stretches, but does not shorten the bodice enough you may need to make the elastic shorter. Once you've determined how long you need your elastic place a mark and trim the excess, making sure to leave about 1/2" tail. Either repeat the process on the other side or use the first as a guide to cut the second.
The collage below shows the elastic laid along the seam, stretching it to sew in, and what it looks like when done. Be careful to make sure your zigzag stays within the seam allowance.
Secure one end of the elastic on the seam, lining up the pin and the mark: I like to use a triple stitch across the seam for this. Using a narrow zigzag on a 0 Stitch length with top sitting so you don't need to turn it is another option. If you secure with a triple stitch: with your needle down lift your presser foot and rotate your top so you can sew along the seam, set your machine to a narrow zigzag. You want to stay within your seam allowance so carefully check your width before you start.
Holding the elastic taunt sew the elastic into the seam. (Shown in the bottom left corner of the collage above.) Do not push or pull as you sew as this can break your needle or damage your machine. This can be a little tricky at first. The tail of the elastic should be long enough that you can pull it from behind the presser foot. With the needle and presser foot down gently stretch the elastic. I like to do this a few inches at a time. I stretch the entire length to make sure the elastic is evenly stretched along the seam, and then grab a point a few inches from the needle, readjusting as needed. Alternatively, you can mark the center point of the elastic and seam, pin these points together and then stretch and pin between the end and center as needed. When you get the the end secure and trim the end of the elastic.
Hem your NSCS and enjoy your fancy new top! Another fun option would be to only lengthen the front bodice and gather by until the front bodice is the same length as the back. This is done by sewing a row or two of basting stitches (long, regular straight stitch) within the seam allowance and pulling one of the threads (just the needle or just the bobbin if using two rows) and spreading the gathers evenly before sewing the side seams.
I know that it is a little difficult to see the seams, the movement of the print is a little deceptive. Here is a close up.