Sewing & Pattern making Terms


Underlining involves adding an additional layer of fabric that mirrors a section of the garment. During the sewing process, these two pieces are treated as a single unit. Underlining is particularly useful when working with sheer fabrics, as it provides an opaque backing. Additionally, underlining can serve as a stabilizing support for fabrics that lack stability.

What is an Underlining?

Underlining is a technique that is done by attaching a layer of fabric directly to the wrong side of the main fabric before construction begins. The underlining and main fabric are treated as one unit throughout the sewing process. Unlike lining, which is a separate layer that hides the inner construction, underlining is visible from both the inside and outside of the garment.

Purpose and Benefits

Underlining serves various purposes, adding both functional and aesthetic value to garments. Let’s explore the benefits of underlining:

  • Enhanced Stability and Durability: Underlining reinforces the main fabric, providing additional stability and strength to the garment. It prevents the fabric from stretching, distorting, or sagging over time, ensuring longevity.
  • Improved Structure and Shape: Underlining helps maintain the desired shape and structure of the garment, particularly in areas such as bodices, skirts, or sleeves. It adds body and substance, enhancing the overall fit and silhouette.
  • Enhancing Fabric Qualities: Underlining can alter the characteristics of the main fabric, such as adding opacity, improving drape, or creating a more luxurious feel. It allows for the use of delicate or sheer fabrics while preserving modesty.
  • Professional Finish: Underlining contributes to a refined and polished appearance, as the additional layer hides seam allowances, prevents show-through, and provides a clean interior finish.

Selecting Underlining Fabrics

Choosing the appropriate underlining fabric is crucial for achieving desired results. Consider the following factors:

  • Compatibility: Select an underlining fabric that complements the main fabric in terms of weight, fiber content, and drape. The underlining should provide support without compromising the intended characteristics of the garment.
  • Similarity in Care Requirements: Opt for underlining fabrics that have similar care instructions as the main fabric to avoid complications during laundering or maintenance.
  • Opacity and Color Matching: Ensure that the underlining fabric is opaque enough to achieve the desired coverage and color intensity. Choose a color that coordinates with the main fabric or remains inconspicuous.

Underlining Techniques

To successfully apply underlining, consider the following techniques:

  • Cutting and Marking: Cut the underlining fabric using the same pattern pieces as the main fabric, making any necessary adjustments. Transfer markings accurately to the underlining for alignment during construction.
  • Basting: Use hand basting or long machine stitches to secure the underlining to the main fabric within the seam allowances. This holds the layers together during construction and ensures they behave as one unit.
  • Seam Allowance Treatment: Trim the underlining seam allowances slightly narrower than the main fabric to reduce bulk. Press the seam allowances open or towards the underlining for a flat and smooth finish.
  • Construction and Finishing: Assemble the garment as instructed by the pattern, treating the underlining and main fabric as a single layer. Pay attention to seam finishes, hemming, and closures to achieve a professional result.


Underlining is a valuable technique that allows seamstresses and pattern makers to elevate the stability, structure and overall quality of garments. By understanding the purpose, selecting suitable underlining fabrics and employing proper underlining techniques, you can achieve impeccable construction, enhanced durability, and refined finishes. Embrace the power of underlining in your sewing projects and unlock a new level of craftsmanship.

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Melissa Villegas
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