Seams
Senior 2 · Home Science
Seams
Lesson 5 of 5
20 min
Knowing how to sew three seams is only half the skill. The other half is choosing the right one for the job, and checking the result. A tailor who puts a bulky French seam in denim, or a pinked plain seam in a child's play clothes, will see the garment come back. A buyer who checks the seams before paying at the market avoids clothes that split after two washes.
This lesson brings the seams together, shows you how to choose between them, and teaches you to spot and put right the common faults.
| Plain seam | French seam | Flat-fell seam | |
|---|---|---|---|
| Rows of stitching | one | two (one shows on the right side) | two (both show on the right side) |
| Raw edges | must be neatened | enclosed | enclosed |
| Strength | medium | medium | high |
| Bulk | low | low on fine fabric, high on thick | medium, but flat |
| Best fabrics | most medium-weight fabrics | fine, sheer, fraying | medium to heavy, firm |
| Time to make | quickest | medium | slowest |
| Article | Seam and reason |
|---|---|
| Sheer voile curtain | French: the fabric is see-through and frays; the seam must be invisible. |
| Denim work trousers | Flat-fell: thick fabric, heavy strain, frequent washing. |
| Lined wool skirt | Plain, pressed open, edges zigzagged or pinked: wool is thick, the lining hides the inside, and a flat seam gives a smooth line. |
| Baby's cotton vest | French or flat-fell: no scratchy raw edges against the skin, and it will be washed very often. |
| Kitenge dress with curved armholes | Plain seams with zigzagged edges; clip the armhole curves so they lie flat. |
| Fault | Likely cause | Remedy |
|---|---|---|
| Puckered seam | thread tension too tight, or the fabric pulled while stitching | loosen the tension, let the machine feed the fabric, re-sew |
| Seam width uneven | the raw edge wandered away from the guide mark | keep the edge against the 1.5 cm mark; tack first |
| Stitching coming undone at the ends | ends not secured | reverse about 1 cm at each end, or tie the threads off |
| Skipped stitches | blunt, bent or wrong-size needle | change the needle |
| Seam split open | stitches too long, or the wrong seam for the strain | shorter stitch; a stronger seam such as flat-fell |
| Frayed allowances | edges not neatened | zigzag, overcast or bind the edges |
| Whiskers on the right side of a French seam | allowance not trimmed narrow enough | unpick, trim to 3 mm, re-sew |
Use a seam ripper (unpicker). Cut every third or fourth stitch on one side of the seam, then pull the thread out from the other side. Never slide the blade along between the layers: it slips easily and cuts the fabric.
Before paying for a garment at the market, or collecting one from a tailor, turn it inside out. Check that the seams are an even width, that the raw edges are neatened or enclosed, that the stitching is straight and not puckered, and pull gently across a seam to see that it holds firm.
Tip
Memory hook: Fine goes French, Force goes Flat-fell, everything else goes Plain and neatened. In an exam, always give a reason for the seam you choose, tied to the fabric or the use.
Choose a seam for (a) a chiffon scarf join and (b) the side seams of school sports shorts in strong cotton. Give reasons.
Solution. (a) French: chiffon is sheer and frays, and the seam must not show through. (b) Flat-fell: sports shorts are worn hard and washed often, so they need the strongest seam with no raw edges.
Habimana's seam puckers along its whole length. Suggest two causes.
Solution. The upper thread tension is too tight, or he pulled or pushed the fabric instead of letting the machine feed it. A stitch that is too long for a fine fabric can also cause puckering.
Explain how to unpick a seam safely.
Solution. With a seam ripper, cut every third or fourth stitch on one side, then pull the long thread out from the other side. Do not slide the ripper along between the layers, because it can cut the fabric.
Mutesi is buying a school shirt. Describe three checks she should make on its seams.
Solution. Any three of: the seams are an even width; the stitching is straight and not puckered; the raw edges are neatened or enclosed; the stitching is secure at the ends; the seam holds firm when pulled gently.
Remember
Sources and credits
