Friday, November 18, 2011

Alterations - Waist-Hip Shaping Part 1: Darts

Welcome back to our miniseries on Alterations! I thought I'd take a short break mid-series to think about how to introduce a bit of theory to help this next section make sense in the big scheme of things. The short break became a long break, with a detour into cardboardland and halloween and party happenings. Well, we're back now and, as our mountain of hideous clothes is growing even as I type this, let's dive right in.

In the last alterations post, we did a symmetrical tuck that took in ease equally from both the front and back of a tank-top. We also hinted that many other alterations (the accurate ones, anyway) involve asymmetrical reduction of fullness i.e. different amounts of ease are removed from the front or back of a garment because of the shape of the body. Today we'll elaborate on that vague concept and then alter a waistband that's too loose to illustrate.

I'm going to start right at the beginning by broaching something I call Waist-Hip Shaping In Lower Garments. Here follows a series of sketches featuring a generic sort of female shape, with curves that are exaggerated for the purpose of illustration. Most non-gestating women have bigger hips than waists. This means that their fitted trousers, shorts or skirts have to be shaped to accommodate this difference. This happens in two main ways:

1 Curved side seams
This accommodates the lateral difference between the waist and hip measurement. In other words, seen from the front or back, a woman's waist-hip region is trapezium-shaped: it is narrower at the waist than the hips.

This is true even for pregnant women! The side seams of a skirt are curved (or at least slanted) outwards from the waist to the hip; they are not vertical lines.
If a garment is stretchy, like a knit skirt or underwear, this curved/slanted side seam probably provides sufficient shaping. There are two side seams, and they are the same on the left and right of the body. 

2 Waist darts
These accommodate the front-to-back difference between the waist and hip measurement. In other words, seen from the side, a woman's lower body is generally wider at the hip level than the waist.
However there is an important difference between this view and the front/back view in the above paragraph: the front profile (waist, abdomen) is quite different in contour from the back profile (waist, buttocks). The front profile (again there are exceptions, pregnant women being among them) is usually flatter and more vertical than the back. 

The contours of a skirt, from this view, would be vertical in the front and sort of slant-y in the back.

However, we would NOT make the back seam slant-y like we would the side seams, because - behold the hideousness - you don't want the back of your skirt to flare out like a rudder:

Center lines and side seams on well-fitting skirts and dresses are vertical- this shows that the fabric is correctly distributed around the contours of the body and isn't pulling or skewed in any particular direction.  In other words, seen from the front or back, well-made skirts have vertical center lines (they may not be actual seams). And seen from the side, well-made skirts have vertical side seams. 

Rather than make the back seam slanty (which makes the side seam slant backwards):

that narrower waist region in the back is shaped with darts instead. This keeps all the seams and center lines vertical.
Very often, these darts are equally spaced on each side of the center back.

Sometimes, there are hollow regions in the front of the body as well. More fitted skirts, or skirts cut for people with more pronounced abdomens, for instance, may have these front darts as well.

The front darts and the back darts are not the same in separation, depth or length. Some tailored skirts may not have front darts, but they always have back darts, because of the more hollow shape of the back than the front region. If this were a post about design and fit and shaping and waist-hip ratios and seam-dart combinations and whatnot, I would go beyond this generalization, but as this is a post on simple home alterations, I will stop here.

Let's now work on a garment that needs darts. In the next post, we'll work on a garment that needs seam-work. Let me introduce The Gaping Waistband!

At first glance, the entire garment looks like it's also too long, and the crotch area is sagging and it's generally unpleasant to look at, but that's largely because the poorly-fitting waistband has slipped down too low over the hips and made everything look sloppy. On more careful diagnosis, it turns out that this pair of pants fits OK at the hips but has extra ease at the waist. I've seen this a lot in my trousers and jeans - years ago, you couldn't buy jeans in six different fits the way you now can. Those of us whose jeans fit our curvier hips often had to wear belts or shove socks in the smalls of our backs just to keep our pants up and the backs of our underwear hidden when we bent over. The excess ease is in the waist region but not in the hips, and so the waist is where we will make the alteration.

To do this, you make a dart (or two). The dart is widest where there is most unwanted ease (the waist) and tapers to a point where there is no unwanted ease (the hips). In theory, you can put this dart (or darts) wherever along the waistband you want, viz:

At the back, just over the fullest part of the buttocks
In the center back as a larger single dart. Sometimes, the zipper region is shaped via a curved back seam to simulate a dart.
On either side of the waist - often this is incorporated into the curved side seam if it is a knit skirt with no back darts, or if the wearer's waist is not especially small compared to her hips.
Split into back darts and front darts, as we mentioned earlier.

Where exactly to put those darts depends on, among other factors:

  • The particular contours of the body. Darts are most effective where the body is most hollow. If you are wasp-waisted but not full in the derriere, place them within the side seams. If you are curvy in the back, place them in the back, and so on.
  • The design of the garment.
  • How deep those darts need to be. Shallower darts are neater than deeper darts because they interrupt the fabric less abruptly. Sometimes you might need to split a deep dart into a few shallower darts. Pintucks in a blouse in place of a bust dart are an example of this.
  • Whether the garment already has darts or seams that may accommodate the effect of those darts. For example, if there are pre-existing darts, it might be a good idea to simply make them deeper rather than create another set of darts somewhere else.

Step 1
Determine how much unwanted ease there is.

The waistband is 2" too loose. We diagnosed this by pinching the center back and finding that a 1" deep dart will make it stay up where it's supposed to be. 

Step 2
Decide where to put this dart. Some considerations for this pair of pants:
  • It has no pre-existing darts, so we cannot, say, sew its old dart 1" deeper. 
  • It is also bulky because of the thickness of the elastic within the ribbed knit waistband so we cannot create a single huge 1"dart.
  • The bulky ribbed knit waistband also makes it difficult to create new darts at the side seam.
Our best bet was to split the big dart into two shallower darts, each 1/2" deep. Emily's back is hollower in contour than the sides of her waist, so we'll put the darts at her back.

Step 3
Mark the center back and then make a mark on either side of that. Mine were each about 1.5" inches to the left and right of the center mark, making them 3" apart. I estimated that the hollowest region of Emily's back where most of the unwanted ease was, was around the central 3" of the waistband. This will be different for different-sized bodies, obviously.

Pinch one of those side marks

 to make the top of the dart

and sew the dart shut. Repeat for the other mark. 

Now there are two 1/2" deep darts, each of which reduced the size of the waistband by 1". The waistband is now smaller by 1"+1" = 2".

Like we did with the tuck in the previous post, we'll fold the darts to one side and sew them flat so they don't stick up. The left dart has contrasting thread to show the stitches; the right dart is what it looks like in reality.

With just two well-placed 1/2" darts, the entire back area of the pants fits better

than it did before. I did absolutely nothing to the crotch seam or side seams or front of the garment. 

Notice that  the hips also look as if they fit more snugly now because the darts are quite long - they extend beyond the bottom of the waistband into the top part of the hip region, taking in a teeny bit of ease there. These darts are quite noticeable, unfortunately, which is a price to pay for buying poorly-fitting pants when I should have sewn them myself, so I knew what I was getting myself into. But they are a casual garment, and Emily wears her shirts out over her waistband anyway, so we'll live with it. 

If this were a real tailored garment, with a faced waistband and lining, you'd of course unpick the waistband, and either deepen the pre-existing darts, or create another pair of darts on both the outer layer and the lining, and then unpick the side seams of the waistband and facing, sew those in to fit the now-smaller waist of the skirt body/lining, and then reattach the waistband. Is it any wonder that waistband alterations don't run cheap? I'd rather sew an entire new garment from scratch. 

Q: Can we use this method to let out a garment (make it bigger)?
A: If there are pre-existing darts, yes. Those darts were created to reduce ease, so if you unpick them and open them out (or make them shallower), you are re-introducing that ease back into that part of the garment. 

In the next post, we'll be working with seam alteration and seam realignment to shape this same waist-hip region. See you then!


  1. Thank you for a very informative tutorial. Now, I'm giving myself away as an inexperienced tailor here, but how did you decide how long to make the darts (i.e., how far down to sew them) and how did you get them both to look equal - I can just imagine that if I sewed them, the darts would look like two different triangles (or in more mathematical terms, how did you get the hypotenuse of each triangle to be the same?) I assume your skills are so much more vast than my own that you're thinking "I just sewed them the same dummy", but I was just wondering if there was a good trick to know.



  2. @Anonymous
    Lisa, this will make you laugh, but I used a secret weapon called The Ruler. I measured and marked the top edge of the dart (the short side of the triangle) and that was 1/2". Then I measured the long side of the triangle, which was as long as needed to extend from the waist level to the hip level (whatever that is, for each wearer), and marked that. Then I joined the two sides with the hypotenuse and sewed on that line. Sometimes I mark (draw) the hypotenuse with a ruler, just to make sure that line is perfectly straight when I sew on it, and sometimes, especially if the dart is a short one, I don't. I am always surprised at how crooked and bulgy I sew that hypotenuse line on a long dart (which then becomes very fat) if I don't actually draw it!

  3. I found it ironic that the brand name of the pants you are altering is the same brand that fits my girls so poorly! I have stopped buying that brand because of that reason!!
    But thanks for a great tutorial, this will be very useful for the pants in storage!!!

  4. Thank you for the detailed explanation!
    Those pants are the exact ones which need alterations for my daughter too.. this year I completely avoided looking at them, but they are the only warm fleece pants in target. They only sell lined ones for boys (which I did buy for my daughter!). I will now try my hand at altering the fleece pants.
    You are a GENIUS ( I know you hear it a lot, but I wanted to say it too) :)

  5. I do wish my sewing teachers had thought to explain the why's and where's of darts as you did above. It makes so much more sense!

  6. I love how you've explained so simply that which may have seemed like such a daunting task to many. Nice work!

  7. This is great! I am a Dart Novice and I was wondering if you have any advice about determining how long to make the darts. Should they end right where the fit is good? A little above that?

  8. Thank you, you made it seem very simple.
    I have sleevless dress with chest darts that don't fit - it is not in the right place also the neck line is to high. I really hope you will show that kind of alterations.

  9. @yifat
    yifat: Unfortunately, I won't be discussing bust darts/ bodice darts at all. It would take too long to explain. To alter a neckline that is too high, you can sew it in i.e. turn the garment inside out so the right sides of the main fabric and the facing are together, and sew a new line of stitching further away from the edge of the neckline. This should give you a lower neckline.

  10. @Laura
    Laura: they should end close to it, but not exactly at the apex (highest point) of the fullest portion. So if it's a skirt dart, don't let the darts reach all the way to the roundest part of the buttocks (or abdomen). For bust darts, don't let them reach all the way to the apex of the bust. This will prevent over-pointedness. Try 1/2" to 1" away from the actual point, and see how it looks. Then change it as necessary.

  11. What about someone with a very pronounced derriere who wants a simple shift dress? The zipper dart does not work. The existing darts, one on each side of the back, have to be 1.5 inches deep each to accomodate the protrusion. Should the two tucks be made into four?

    1. Anonymous, I don't remember if I replied to your question before or not but I'm replying here in the hope that you might read it. Without seeing the dress on you, it's hard to say what to do to just the darts to improve the fit. I'd hazard a guess and say yes, in theory, the two darts could be made into four (two on each side of the center back). The side seams can also be shaped. A lot depends on how snug you want the dress to be and how stretchy the material is.

  12. This is old stuff but thank you! I'm aiming to learn how to alter clothes to fit, since I'm petite and don't much care for shopping...and it's hard to find clothes that fit well without doing a lot of shopping. Thank you!

  13. This is a very good tutorial. It's so detailed. Thank you!


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