Why do we need to include Staystitching and Understitching in garment construction?

A short post this week.  However, I am covering two techniques vital to a high quality finish on garments.  Both these techniques are mentioned in pattern guidesheets but are often overlooked.

Staystitching is used to prevent outer seams (curves) stretching during construction and fitting.  It is a very important technique and should not be omitted from the construction process.

Done on a single layer of fabric, the stitching line should be made with small stitches (1.5-2.0) and lie within the seam allowance and no further than 3mm / 1/8” from the sewing line.  The stitches are positioned close to the seam line for maximum control of the seam.

Staystitching just inside the seam line.

Staystitching just inside the seam line.

They also protect the seam stitching when the seam allowance is clipped to allow it to spread inside the garment when the seam allowances flip to the wrong side.

Tip: Position the fabric to cater for the 15mm / 5/8” seam allowance and move the needle one to two positions to your right so that the stitching sits very close to the seam line but not on the seam line.

Staystitching needs to be done directionally with the grain of the curve or from widest to narrowest in straight areas (for example, shoulder seams):

 

Directional staystitching will preserve the grain

Directional staystitching will preserve the grain

Curved areas:

  • From shoulder to centre front
  • From shoulder to centre back

V necklines:

  • From centre front to shoulder

 

V necks are stitched from bottom of V towards shoulder. This will result in both sides of the V laying flat when the garment is complete.

V necks are stitched from bottom of V towards shoulder. This will result in both sides of the V laying flat when the garment is complete.

  • From centre back to shoulder

Waist edges:

  • From side seam to centre front

 

Waist staystitching - especially useful when applying a yoke.

Waist staystitching – especially useful when applying a yoke.

  • From side seam to centre back

Staystitching is also essential where it will be necessary to clip to a corner point during the construction.  Most pattern guideline sheets indicate staystitching up to the marked point and away from it at 90° followed by an instruction to clip up to the point.  This often results in staystitching remaining visible once the seam is sewn and can cause the clip to expand beyond the point while manipulating the fabric.

As an alternative, I usually staystitch to the point within the seam allowance, using a 30° angle, and leave the clip until it is necessary to move the fabric.  I find this results in a sharp, strong corner.

Staystitching in a narrow V instead of right angle still protects the point as it is cut and will not result in staystitching being visible in finished garment.

Staystitching in a narrow V instead of right angle still protects the point as it is cut and will not result in staystitching being visible in finished garment.

Understitching helps the facings to roll to the inside of the garment, giving a smooth outer edge and helping to keep the facing and/or lining from showing during garment wear.

It should always be used, even if the edge of the garment is to later be topstitched.

Once the facing seam allowance has been notched or clipped, lightly press it towards the facing/lining.   With the garment right side up, stitch through the facing and the seam allowances  at 2-3mm from the seam line and on the inside of the garment.

Understitching applied to the facing will hold the seam allowances in place and allow a soft roll on the outside of the garment and no facing showing.

Understitching applied to the facing will hold the seam allowances in place and allow a soft roll on the outside of the garment and no facing showing.