Garment Construction and Sewing Techniques
What the exam tests
This domain tests whether you can select and execute seams, stitches, hems and closures suitable for a fabric and garment. It rewards knowledge of machine settings, pressing and neat finishing.
Core rules and concepts
- Common seams are plain, French, flat-fell, lapped and welt. Plain seams are quick but need neatening; French seams enclose raw edges; flat-fell seams are strong and show topstitching.
- Stitch types include straight stitch, zigzag, overlock and chain stitch. Match needle size and thread to fabric weight; test on a scrap first.
- Balanced machine tension gives equal needle and bobbin thread interlocking inside the fabric. Correct stitch length for medium cotton is about 2.5 mm, or 10 stitches per inch.
- Press as you sew: press seams flat, then open or to one side. Pressing is not the same as sliding the iron.
- Finish hems with single or double turn, blind hem or facing. Add interfacing where buttons and buttonholes need support.
Worked example
A sheer organza blouse needs a seam that is neat on the inside and not bulky. Choose a French seam. Sew a 1 cm seam with wrong sides together, trim to 3 mm, press, turn right sides together, and stitch a second 6 mm seam enclosing the first. The reasoning is that organza frays and a plain seam would show raw edges through the sheer fabric; a flat-fell seam would add bulk. A French seam gives a clean enclosed finish with minimal thickness.
Traps that cost marks
Ignoring tension, using a blunt needle, pressing instead of lifting and placing the iron, trimming a seam too close, and forgetting to test stitch length are common errors.