A flat fell seam you say? What on earth is one of those? Well luckily for you I am about to tell you.
Are you wearing jeans? Well look at the inner leg seam, you can see two lines of stitching right and a sort of bump all the way along the seam. This is a flat fell seam and you find it on most jeans here because its a super strong seam that works well for the heavy denim fabric. Also its particularly good on the inner leg where the jeans take a lot of wear and tear. So without further ado, let's sew a flat fell seam:
First off place your fabric pieces with the wrong sides together, this is the opposite way to normal, so that the good sides are facing out. Then sew your seam using your usual seam allowance.
Using your dressmaking scissors trim 1 (but only 1) of your seam allowances down to half the width, you'll end up with one wide one and one narrow one.
Now press your seam open from the wrong side of your fabric. Then turn it over. Then fold and press the wider seam underneath the narrow one.
Finally top stitch along the folded edge of the wider seam to secure it down. Then give it one final press and hey presto, a flat fell seam.
If you are making yourself a pair of trousers then this is a great technique to have under your belt before you start. Be careful though, you won't be able to use this type of seam on both the inner and outer leg seam because of the way it is constructed. Make sure you sew the inner leg seam first if you want to use this technique. I learnt this the hard way and had to unpick my outer leg seam when I first tried it. Luckily you can learn from my mistakes. Have fun. Zoe x