Hi everyone, Angela here. In this video I'll show you how I take in the back waist and seat of a
pair of jeans for my client. For her fitting I folded right along the centre back seam
and pinned firmly exactly to her body shape. I'll be sewing this alteration on my Brother industrial
sewing machine. Links for all the tools I use can be found in the description below.
The back of the jeans are sewn together with what's called a flat felled seam .
If you look closely, the edges are folded into each other and there's a double
row of stitching that goes through all the layers creating a very flat and strong seam.
When jeans are being made, the sides of each piece are fed through attachments that overlap the seams
and then a twin needle stitches through all the layers creating the flat felt seam.
When you have a plain seam where the two layers are sewn together with a straight stitch and the
edges are serged or overlocked and the seam isn't flat it's very easy to do alterations,
because all you need to do is stitch beside the original seam line. But when you have a flat
fell seam, you'll need to unpick the stitches from the back and then pull the layers apart.
You'll notice that the seams aren't equal, so it's a bit more complicated to do this alteration and
get the same finish. Start by marking the outside of the jeans by chalking along the pins exactly
where they were put in on both sides of the back. Make sure to mark from the very top of the waist
down to the bottom of the last pin. Now remove all the pins. Chalk again over your marks to create a
smooth solid line on both sides. These lines when joined will be your new back seam. Even though I
folded along the edge of this seam when pinning, that is actually not the true centre of the back.
If we measure across the pocket corners, the true centre is actually between the double stitching on
that seam which continues right up to the loop. I'm using a single edge razor to remove the back loop.
Now you can either razor between the loop and the waistband or you can razor between the layers of
the loop itself which is a bit safer. Either way, just be careful not to cut the fabric of the jeans.
Remove the labels from the back of the waistband and then we just have to separate the waistband
from the rest of the jean. So you can either use a razor blade or if you look at the back of the
waistband, if it's a chain stitch, you just have to clip a couple of the stitches and pull on the
correct thread for the stitching to unravel. so when i did the fitting I used this seam as the
center which means I folded it along here on the waistband. Now there's going to be a join when we
sew the waistband together but I don't want it to continue up from the seam. I want the loop to
cover it. I need to move the position of the new join 1/4" to the left. So that it'll
end up between the stitch lines, we just have to shift both of the new seam lines on the waistband
1/4" over to the left. We just need to ignore or remove the original chalk line here
and the original chalk line here. I'm putting pins in the new seam lines so that you're clear with
what i'm doing. This will all make sense when it's joined together. Now we need to add some
seam allowance. Chalk a line ½" to the right of that seam line where the pin is
and on the other side, chalk a line ½" to the left of the seam line where the pin is.
Cut on the lines that were just drawn and the waistband is now ready to be sewn in the correct
shape. You can put aside the waistband for now but one thing to make note of is that if you have a
patch on the waistband, it might be in the way of sewing on this waistband. There's plenty of
room but if you do have one that's in the way, you'll need to remove it and reattach it later.
Now this next step you don't have to do but what I'm going to do is draw a chalk line
on both sides down that original centre seam so that I can show you what's happening underneath.
The next step is to go in and unpick those two rows of stitching to about
an inch below the chalk marks. Place a pin there and turn the jeans inside out.
I'm just chalking where the pin is so that you can see.
Again, we have two rows of chain stitch that we can unravel.
Just clip where the chalk mark is. Start at the top and unpick the stitching down to that mark.
If your jeans are a little bit older, you might have some trouble unraveling the stitches. The
fibers tend to knot up a little bit so you'll just have to clip some of the stitches as you go along.
Now you can pull out your top threads easily all the way down to the pin.
When we pull the back of the jeans apart, on the left we can see that there is just
under ½" of seam allowance and on the right there's about 1" of seam allowance.
We now have to mark and continue those different seam allowances along the new seam lines for each
side. With the right side up, lay the left side of the jeans down flat and pin the waistband
out of the way. Use a grid ruler to draw a ½" seam allowance along that new seam line.
Now because the original seam allowance is actually just slightly less than ½",
I'm going to cut just a little bit on the inside of the chalk line.
Next, lay down the right side of the back, pin the waistband out of the way, use the grid ruler to
mark out the 1" seam allowance from that new seam line and then cut along the new chalk line.
Flip over the left side. With the wrong side up, we want to continue along with that half inch seam
allowance. So press along the chalk mark and also press out any of the original creases so that you
have a nice flat seam. Turn over and check that you have a nice smooth curve without any points.
Now let's do the other side of the jeans. This time, turn the seam allowance in the opposite direction.
Flip the edge so that it meets up with the chalk line. You're still turning and
pressing ½" seam allowance, but this time towards the outside of the jean.
If you take a closer look at the seams, you can see that the right side is sandwiched in
between the left side and then folded over before it's stitched down.
If you don't have thread that matches the original stitching perfectly, you may want
to unpick all the way down to the crotch. Now turn your jeans inside out. It's very hard to
sew through all the layers keeping the folds in place. So what I do first is sew a holding stitch.
To do this, place the edge of the under layer right into the fold of the top layer.
Fold the top layer over and place a pin through the seams. You really want to make sure the edge
is butted right into that fold. You should be able to feel it with your fingers. If it's not accurate,
the seams on the inside may look too wide and the stitching may not sew through all of the layers.
It's also important to match the seams of the yoke going across the seat. Match the seams
along the chalk lines and pin it in place through the fold line before flipping the top layer over
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If you need to use the same thread right down to the crotch,
unpick the rest of the original top stitching and pin all the way down.
Starting at the bottom near the crotch, stitch a line through the centre of that seam
to hold all the layers together. Remove your pins as you sew
and check at the same time the edge is still tucked into the fold.
When you get to that really thick seam, use a tool to help keep the fabric in place
and to keep the fabric folded over. You may need to carefully hand wheel over this thick seam to
avoid breaking a needle. One other step I do is sew just where the pin is to hold that seam in place.
Place your needle down in between the two horizontal lines of stitching
and just slightly to the right of the fold. Sew a couple of stitches to hold it all in place.
Turn over to the right side and check that the seams are perfectly matched.
So this holding stitch that was just sewn isn't going to show on the outside.
It's just there to hold the seams together. So when the seam is folded down to do the topstitching,
it won't shift or come apart. Next, we'll do the topstitching with the jeans still inside out.
Because the seam was pressed earlier, we can now lay the back seam into position
along that folded edge. Stitch about ¹⁄₁₆" beside the fold.
When you get down to the bottom near the crotch, just pivot, stitch across, pivot again and sew the
second row of top stitching. This way you don't have to stop and start a new row of stitching.
Use the original marks to determine the width between the two rows
and continue sewing parallel to the first row back to the top.
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Next, we'll sew the inner waistband first. Put right sides together and match the top folded edges.
Place a pin through the folds so that they'll match perfectly when sewn together.
Then repeat for the bottom edge.
Notice that this seam has a couple of angles. Make sure to sew the 1/2" seam
following these angles.
I"ve ironed the seam open and also ironed the top and bottom edges so they're nice and smooth. Even
though the seam was on quite an angle, you don't want to have points at the top and bottom of the
waistband. Fold the outer waistband out of your way. If you want the label back on, centre and reattach.
Next put the right sides of the outer waistband together.
And again match the edges and folds and stitch together following the angles.
Open the seam, fold the top and bottom edges and iron if you need to. Match the top folded edges
and stitch together along the original marks. Backtack at the start and finish.
Fold in the bottom edges of the waistband and you can see that seam is in the center
between the top stitching. Place the waistband back on the original position.
Pin through all the layers and check to make sure you've pinned the back edge as well.
Stitch the bottom edge of the waistband, back tacking at the start and finish.
Clean off any bits of the original thread from the loop.
If it's all feeling a bit thick, hammer down the edges a bit.
Center the loop on the waistband covering the seam. Start your stitching by putting the needle
in the center of the loop. By starting here, the presser foot doesn't push the loop out of position.
Stitch to the edge, reverse back to the other edge and then stitch back to the centre again.
You can do this a couple of times for added strength. Line up the side of the loop with
the edge of the seam and sew the bottom edge in the same way. If you have any problems balancing
your presser foot, you can slide a little piece of cardboard under it to level it out.
On the inside, you have a professional looking flat felt seam with an extra holding stitch
in the middle. On the outside, your seams match, your loop covers that waistband seam and the
pockets are evenly spaced from the center of the back seam. Make sure to check out more of
my sewing tutorials. Thanks again for watching. Until next time, take care and Happy Sewing!