How to Take in Waist and Seat of Denim Jeans- Make Jeans Smaller ( Clothing Alterations) | Angela M | Skillshare

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How to Take in Waist and Seat of Denim Jeans- Make Jeans Smaller ( Clothing Alterations)

teacher avatar Angela M, Business Owner, Seamstress, Designer

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Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Watch this class and thousands more

Get unlimited access to every class
Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Lessons in This Class

8 Lessons (22m)
    • 1. How to Take In Back Waist of Jeans

    • 2. Tools

    • 3. What is a Flat Felled Seam?

    • 4. Marking and Cutting

    • 5. Pressing

    • 6. Stitching Together

    • 7. Completed Alteration and Fit

    • 8. Class Project

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About This Class

In this class, I show you step by step how to take in the waist and seat of a pair of denim jeans for the perfect fit.

It’s not as scary as it looks to take apart a pair of jeans and put it back together and have them looking like original.

The centre back seam of most jeans are joined by what’s called a FLAT FELLED seam.  This seam is made by overlapping and folding the edges of both sides and then double stitching through all layers.

The result is a flat inner seam that is very strong.  This type of seam is also great in children’s wear and bags.

The method I use is very accurate for doing jean alterations for each individual.  It follows the curves of the body rather than just taking a measurement and reducing the waistband by that amount.

It is a good idea to practice and complete the class project before doing the alteration on your jeans.

Please share and review if you found this class helpful

Thanks for joining my class and see you in my next one!

Meet Your Teacher

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Angela M

Business Owner, Seamstress, Designer


Hello, I'm Angela.

I’m a professional seamstress and business owner with over 35 yrs professional sewing experience.

I work with everything from simple casual wear to designer bridal and leather wear.

I specialise in clothing alterations helping clients get that “perfect” fit.


Over the years, I’ve developed easy to follow techniques to ensure consistent quality results. 

So if you ever thought about turning your passion for sewing into a business, my classes will help you with your sewing skills, speed, workmanship and efficiencies


Hope you enjoy my class and Happy Sewing!




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1. How to Take In Back Waist of Jeans: Hi, I'm Angela. Welcome to my shop and thanks for stopping by my class. In this class we will take in the back waist and seat of a pair of jeans. So you'll need someone to help you do your fitting by pinning from the waist down exactly to your body shape. 2. Tools: To do this alteration, I'll be using a grid ruler, some chalk, clippers, sharp scissors, and a razor blade, And I'll be sewing it on my industrial BROTHER sewing machine. 3. What is a Flat Felled Seam?: 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 to create that flat and really strong 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 FELLED 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 lot trickier to do this alteration and get the same finish. 4. Marking and Cutting: We start off 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. Now 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 back edge of this seam when pinning, that is actually NOT the true center of the back. If we measure across the two pocket corners, the true center of the back is actually between the double stitching on that seam, which continues right up to the loop. Next, I'm going to use a 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. Next, remove the label from the inside of the waistband and then just pin that label and your loop to the side of your jeans so you that you don't lose it. Next, 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 on the back of the waistband, if it's a chain stitch, you just have to clip a couple of stitches and pull on the right thread for the stitching to unravel. So as I said before, when I fitted these jeans, I used this seam as the centre, 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. So I need to move the New join ¼” over to the left. So that it’ll end up between the stitch lines. So we just have to shift both of the new seamlines on the waistband, 1/4” over to the left. So now we just need to ignore or get rid of that original chalk line there. And the original chalk line there. I'm just going to put 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. We've basically just shifted the seam on the waist so that it’ll end up in the true center. Now we have to add some seam allowance. Chalk a line ½” to the right of that seam line where the pin is. And then on the other side, Chalk a line 1/2” to the left of that seam line where the pin is. Now cut on the lines that we've just drawn. The waistband is now ready to be sewn in the correct shape. And we can put the waistband aside for now. But one thing to make note of, is if you've got a patch of some sort 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 can just remove it and reattach it later. Now this next step you don't have to do, but what I'm gonna do is draw a chalk line on both sides down that original Center seem 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 the pin there and then turn your jeans inside out. I'm just going to place the chalk mark where the pin is, so that you can see. Again, we've got two rows of chainstitch that we can unravel, just clip were that chalk mark is so that it stops there. Start at the top and then unpick that stitching down to that chalk 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. Once you've done that, turn your jeans back to the right side. So 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 an inch of seam allowance. We now have to mark and continue those different seam allowances along the new seam lines for each side. Next lay the left side of the jeans down flat and pin the waistband out of your way. Use your grid ruler to draw a 1/2” seam allowance along that new seam line. Now because the original seam allowance is actually just slightly less than ½”, I'm just going to cut a little bit on the inside of that chalkline. Now lay down the right side of the back and pin the waistband out of the way. Use your grid ruler now to mark out the one inch seam allowance from that new seam line. And then cut along that new chalkline. We’ll now be able to press the seam allowances into its new shape. 5. Pressing : Let's turn over the left side of the jeans. We want to continue along with that 1/2” seam allowance. So press along your chalk mark and also press out any of the original creases so that you have a nice flat seam. Turn over and make sure you have a nice smooth curve without any points. Now let's do the other side of the jeans. This time you're going to turn your seam allowance in the opposite direction. So take your edge and flip it until it meets up with the chalkline. You're still turning 1/2” seam allowance, but this time towards the outside of the jeans. So 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. Here, we can look at it from another angle with the seam allowances facing opposite direction so that they can overlap each other. Now another thing I want to mention is that if you don't have threads that matches perfectly, you may want to unpick your threads all the way down to the crotch. That's totally up to you if you don't want to see a change in thread. Next, turn your jeans inside out. Now that we're on the inside of the jeans, take a close look again at how the seams are overlapped and then folded before the topstitching is done. Now it's very hard to sew through all these layers and keeping all the folds in place. So what we need to do first is sew a holding stitch. To do this, you want to place the edge of the underlayer right into that fold of the top layer, Fold it over and then place a pin through the seams. You really want to make sure that edge is RIGHT INTO the fold and feel it with your fingers that you've done it. If it's not accurate, the seam on the inside of the jeans may look too wide and the stitching may not sew through all the layers. Another thing that's important is to match up those seams that go across the seat, match the seams along the chalk lines and then place a pin so that it holds it in place before we flip the top layer over. If you've decided that you want to use the same thread all the way down to the crotch. You'll have to unpick the rest of the top stitching now and then continue your pinning all the way down. 6. Stitching Together: Starting at the bottom near the crotch, stitch a line through the center of that seam just to hold all the layers together. Pull out your pins while you're sewing and just double-check again that that edge is tucked right into the fold. When you get to that really thick seam, use a tool to keep the fabric in place and to keep it folded over. You might need to hand wheel over this seam so that you don't break your needle. Another thing we'll do is just stitch Where that pin is to hold that big seam in place. Now place your needle just between those two lines of stitching. And we're gonna stitch just slightly right of the fold. We just need to do a couple of stitches to hold it in place. And then just check on the right side that the seams are matching up perfectly. So this holding stitch that we've just sewn isn't going to show on the outside. It's just there to hold all the pieces together. So when this seam is folded over to do the topstitching on the other side, nothing's going to come apart. Next we're gonna do the topstitching with our jeans still inside out. Because we've already pressed that seam earlier, We can now lay that back seam into position along that fold. We’ll now edgestitch along the seam about 1 /16th’’ to the left of the fold. When you get down to the bottom near the crotch, just put your needle in, lift your presser foot and pivot. Do a couple of stitches and pivot again and continue your second line of topstitching. By doing it this way, you won't have to start and stop a new row of stitching. Now keep sewing along that line that's still showing on the jeans And also use the outer edge of your foot and keep it parallel to the first row of stitching. So our back seams are matching up nicely and our pocket corners are pretty level and equal distance from the center of that back seam. Next we're going to sew the inside of the waistband together. place the right sides together and match the top edges. You want to put a pin right through the two folds so that they match perfectly when you stitch them together. Do the same thing for the bottom edge, matching the folds and then putting a pin through both layers through the fold. You'll notice that this seam has a couple of angles. So we want to sew our 1/2” seam allowance following those same angles. Next, we just have to head over to the iron to do some pressing. Okay, so I've finished ironing this seam open flat, and also ironed the top and bottom edge of the waistband so it's nice and smooth. So even though this waistband is on quite an angle, you don't want a point there and you don't want a point there. With the inside of the waistband facing you, Just flip the other side of the waistband out of your way and pull down the top part of that jean So it's not near the waistband. It's at this time you want to Sew the label back on, most of my clients don't care about the size label. They just want the brand label back on. So you can just centre the label and stitch down the two sides or you can stitch all around the label. Okay. My client has decided that she doesn't want any labels in her waistband, So let's go ahead and join the outside pieces of the waistband together. Ignore your chalk marks and place the right sides together, matching the top and bottom edges. Again, we want to pin through those folds so that they match up perfectly and to keep the fabric from moving. Stitch a ½” seam following those angles of the waistband again. Now open up that seam and just press it with your fingers if the denim is soft enough, otherwise go over and press it with the iron. Now fold over the top and then line up the two top edges of the waistband together. Now again, if your thread is quite different, you can unpick all the way back to the loop and start stitching from there. But on this pair of jeans I won't bother because it's just black. Stitch along the edge through all the layers and just follow the line that's still showing along the denim. Makes sure to backtack at the beginning and end of your stitchline. I like to cut my threads really clean while I'm sewing, so I don't have to do it later. Next, we're going to turn under the bottom edge of the waistband making sure that the center seam is open flat. You can see the join of the waistband matches the center of the jeans between the two topstitches. Place the waistband back on to its original position. You can see where it goes because the color of the denim is different. We want to make sure when we're sewing that it's going to be catching all the layers. So just put a pin through the top and bottom layer of the waistband through the stitchline. Now the last step is to attach the back belt loop. Now when I originally razored this loop off, the threads from the original stitching are still there. Make sure you clean these threads out. It's really not nice to leave it on and then stitch on top of it. If your loop’s a bit thick, you can just hammer down the ends. Position your loop in the center of the waistband on top of the seam, And then put your needle through the middle of the loop. By starting your sewing this way, the presser foot won't push the loop out of position. Go forward just enough stitches until you cover the edge of the loop. Then reverse and stitch until you get to the other edge. Stitch forward again to the edge and then reverse back to the center of the loop. I find by starting and stopping the stitching in the middle, you don't end up with threads on either side of the loop. To sew the bottom of the loop just line it up with the centre back seam And again, start off by putting your needle through the center. If you have any problems balancing your presser foot, you can just slide a little piece of cardboard to level it out. Then finish off sewing it just like we did the top. Your waist and seat alteration to these jeans is now complete. 7. Completed Alteration and Fit: Just a quick recap to look at our completed alteration. We now have a small little Waistband Our seams at the back match nicely. Our loop covers the seam in the waistband. Our pockets our level and evenly spaced apart. On the inside you have a nice neat, professional-looking FLAT FELLED seam with an additional holding stitch in the centre. Most importantly, we have a happy client with jeans that fit her. 8. Class Project : For this project, you'll need two pieces of fabric, approximately 4 inches wide x 8 inches long. A grid ruler, some chalk, clippers, and some thread. On the right side of the fabric, Use your grid ruler and draw a line 1/2’’ in from the edge. And then on the other piece of fabric, draw a line 1’’ in from the edge. Flip your first piece of fabric over to the wrong side and then turn that edge that half an inch along your chalk mark and press, try to press just slightly less than half an inch. Now flip it over so it's right side up again. For the second piece, keep it right-side-up. Turn the edge so that it just meets the chalk mark. Press along the entire edge this way so that you have a 1/2’’ turn. Now place the first piece on top of the second and just turn it over So the wrong side is up. Push that edge into the fold of the second piece. It's important to get that edge right into the fold. Put some pins all along that seam to hold everything in place. Then turn it around. Now stitch a line right down the middle of that seam. Now turn it around and open it up to the right side. Now we're not going to open it up and pull it tight along the stitching. We're going to let it relax on its fold that we pressed earlier so that the edges stay overlapped properly. Next, we're going to edgestitch along that fold approximately 1/16’’ to the left of it. Now we'll sew a second row of stitching. We’ll make it approximately 1/4’’ parallel to that first edgestitch. There you have your finished flat felled seam with beautiful parallel stitching on the front and on the back you've got three rows of stitching keeping that seam nice and strong. Thanks for joining my class and we'll see you in the next one.