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Threads eLetter

Excerpted from Fast Fit

Problem Areas: The Back

In Fast Fit, Sandra Betzina offers innovative, simple, and straightforward approaches to sewing clothing with the best possible fit, and ultimately, the most flattering look. In this excerpt, she explains how to adjust a pattern for broad and narrow backs.

Broad back

The problem
If the back of your garments feel tight and the back armhole seamlines often rip out, then you're all too familiar with the broad back overfitting problem. The dilemma with ready-to-wear is difficult: If you buy a garment that fits in front, the back is too tight. Yet, if you buy a garment to fit your back, there's too much fabric in the front.

Few of us have bodies that are divided in perfect halves, so that the front of the body is the same width as the back. This is particularly true when comparing the upper back to the upper front chest. Many people are one size in front and one or two sizes larger across the back. Sometimes age, too, can cause a rounded back and narrowed upper chest. Whatever the case, pattern alterations can dramatically improve your garments.

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FAST FIT solution
On a single-size pattern, add a vertical extension from the shoulder to the hemline. If your pattern is multisize (see Simple sizing), use a size or two larger when cutting the back. To join the seamlines, add an easeline across the back shoulder or, for large alterations, create a dart in the middle of the back shoulder.

Step-by-step solution
  1. Purchase a pattern that fits your front upper chest and adjust the bust to fit (if necessary) by adding at the side seams.
  2. Take a flat pattern measurement across the back pattern piece at the armhole notches, from the side seamline to the center back. Multiply this number by two.
  3. Compare the pattern measurement to your own cross back measurement, plus the amount of ease you want. A good rule of thumb is 3/4 in. to 1 in. (1.9cm to 2.5cm) of ease across the back. The difference between these numbers is the amount you need to alter your pattern.
    STEP 4: On the back, draw a line from mid-shoulder to hem, parallel to the grainline. The pattern will be cut apart on this line.
  4. On the back pattern piece, draw a line from the center of the shoulder to the bottom of the garment, making the line parallel to the grainline. Cut the pattern in two along this line.
  5. Halve the alteration amount that you determined in Step 2. Cut a pattern paper extension to this width and insert it, taping it down, between the two halves of back pattern piece. True up the shoulder seam.
  6. With this alteration, the back shoulder seamline is now longer than the front. If your pattern alteration is less than 1/2-in. (1.3cm) wide, an easeline across the back shoulder makes them the same length. If your addition to the back is more than 1/2 in. (1.3cm), you'll need to create a dart in the middle of the back shoulder. Make the dart as wide as the pattern alteration and 3 1/2 in. (8.1cm) long from the shoulder cutting line. Or you can put only some of the back addition into the dart and ease the remaining 1/2 in. (1.3cm). The dart can be curved if the upper shoulder is rounded. Then sew the shoulders together with the back closest to the feed dogs. Small darts can be short; wide darts need more length to end smoothly.
STEP 5: Adding a small amount of width from top to bottom along the back makes a more comfortable garment for those with a broad back.
STEP 6: Ease or dart out the excess back shoulder width so that lengths of the front and back shoulder seams match.

Narrow back

The problem
A narrow back is quite common on people with very erect posture. You may have either been born with an upper-torso fitting problem or adopted an erect posture through force of habit. If your garments have vertical wrinkles up and down the back, and horizontal wrinkles between the shoulder blades, it's a good indication that you have a narrow back. From shoulder to waist, your entire back is proportionally smaller than your front.

In this case, both a horizontal and a vertical adjustment are necessary. A typical back alteration is 1/2 in. (1.3cm), but you may need to fine-tune your alteration. The ideal style for you is one in which the back seams extend from shoulder to hem, so you can take in the seams. Today's Fit patterns by Vogue and Butterick patterns often feature this type of seaming. Whether the entire back -- or just the top half -- is narrow, the following instructions help create a smooth, wrinkle-free back.

FAST FIT solution
Reduce the back pattern piece both horizontally and vertically to eliminate all wrinkles. Ease the different-length shoulder seams together. Reduce the sleeve back with a horizontal tuck to match.

Step-by-step solution
  1. Draw a vertical line, parallel to the grainline, from mid-shoulder to the waist of the back pattern piece. Draw a second line 1/2 in. to 3/4 in. (1.3cm to 1.9cm) away, toward the armhole.
  2. Make a horizontal cut from the waist at the side seam to the vertical lines, so that the pattern is not reduced below the waist. Fold and tape the pattern piece together along the lines, then true up the side seams. This takes care of the vertical wrinkles above the waist.
  3. True up the shoulder seam, keeping the neckline size intact. Because the front shoulder is now longer, ease it into the back by sewing with the front shoulder against the feed dogs (see Joining uneven shoulder seams).
  4. To eliminate the horizontal wrinkles, draw a horizontal line across the back pattern piece just above the sleeve notches at the armhole. Draw a second line 1/4 in. to 1/2 in. (6mm to 1.3cm) above it, parallel to the first. Fold and tape the pattern piece together along the lines.
  5. On the sleeve, draw a horizontal line across the pattern above the notches. Fold out a horizontal tuck in the sleeve back only, tapering to zero by the sleeve front. Smooth out the cutting line on the back of the sleeve cap. Do not change the location of the shoulder placement dot on the sleeve cap; ease the front into the back shoulder when sewing.
STEP 3: For a better fit on a narrow back, reduce the pattern both horizontally and vertically above the waist. If you need width below the waist, add at the vertical seams.
STEP 5: Whatever is taken out horizontally in the back must also be taken out of the sleeve. The reduction should taper to zero by the sleeve front.

Sewing expert Sandra Betzina, the host of HGTV's Sew Perfect and author of Power Sewing Step-by-Step and Fabric Savvy, teaches hands-on classes in San Francisco. For information, call 415-386-0440 or visit her web site,

Photos: Sloan Howard; Drawings: Shawn Banner

From Fast Fit, pp. 82-88
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