the top of pants or skirt is finished with facing when a)extra strength is required at the waistline 2)its not possible to layer the fabric 3)a stay tape cant be used at the seams or 4)you don't want the waistband to be visible from the right side
I feel the answer is 1)because
the waist needs to be strong as it fits the body closely and has to support the weight of the skirt or trousers and need interfacing to support it
You asked about facing which is different from interfacing. Interfacing is used to stiffen the band so that it doesn't roll or wrinkle up.
When the top of a pair of pants or a skirt is finished with a facing, there are several reasons for choosing this method over other techniques:
1) Extra Strength: Sometimes, the waistline of pants or skirts needs to withstand extra pressure or tension, especially if they have a snug fit or heavy fabrics are used. In such cases, a facing is a suitable option as it provides additional strength and stability to the waistline.
2) Fabric Layering: If it's not possible or desirable to add extra layers to the garment, such as in lightweight or transparent fabrics, a facing is a good choice. Instead of adding a separate waistband, a facing can be integrated seamlessly, maintaining the garment's overall appearance.
3) Incompatibility with Stay Tape: Stay tape is a narrow, stable tape that can be used to reinforce seams. However, there may be situations where it's not feasible or advised to use stay tape at the waistline, such as when the fabric is delicate or prone to fraying. In such cases, a facing can provide a secure and clean finish to the waistline.
4) Concealed Waistband: Some designs call for a streamlined and minimalistic appearance, where the waistband is not intended to be visible from the right side of the garment. In this scenario, a facing can be used to finish the top edge of the pants or skirt while keeping the waistband hidden.
To create a facing, you can cut a separate pattern piece that mirrors the shape of the waistline. This piece will be attached to the top edge of the pants or skirt, usually with right sides together. After stitching, the facing is folded to the inside of the garment and can be secured by understitching or edge stitching. Finally, the raw edge of the facing can be finished with a serger, zigzag stitch, or bias binding for a clean and professional look.