Before following this tutorial, it will help to read our notes on the sleeve block here first.
If you want to make floaty, flared sleeves, this is one of the simplest things to do! It’s based on the “slash and spread” principle. The main thing to remember is not to just widen the sleeve at the seams, as that will be the only place you’ll add any volume. Instead, trace off your sleeve pattern at the desired length (including a seam allowance for the hem).
Then draw several straight vertical lines from the sleeve head down to the hem (they should be at right angles to the hem). Here I just used the width of a standard ruler to keep mine evenly spaced.
Cut along all the lines you have drawn, from the hem upwards. Do not cut right through the pattern piece, but leave a few millimetres at the top.
Now spread out your strips of sleeve on top of a piece of pattern tracing paper. Spread them a small distance from each other for a slightly flared sleeve, and a wider distance from each other for a very flared sleeve. Make sure that the distance between each piece is the same.
Pin or tape this spread-out sleeve piece to the pattern tracing paper below.
Draw around the edge of the sleeve shape you have just created, and cut out your new pattern piece.
Cut out your new flared sleeve, and attach to your dress! Once you have sewn the shoulder seams, pin the sleeves to the armholes. Pin the centre point of the sleeve to the shoulder seam, and the edges of the sleeve to the armhole edges. Then pin along the sleeve cap every inch or so, easing the two pieces together where necessary.
Sew the sleeves to the armholes with a 3/8” seam allowance, and press the seams towards the sleeve.
Sew the side seams and sleeves of your dress in one continuous seam from top to bottom. Press and hem the sleeve as desired.