SEAM ALLOWANCES

The reasons for including seam allowances in the blocks and retaining them during pattern construction are discussed in the Special Note on page 4. It is recommended that the note be read before continuing with this section.

Working with Seam Allowances

A 1cm seam allowance is allowed on the blocks except where stated no seam allowance. Therefore if a seam is required at the centre back or side seam of the casual blocks or over garment blocks, seam allowance must be added. The fitting line on the blocks is marked with a dotted line, this shows clearly which lines have seam allowance added. Where seam lines are drawn and the block is separated, seam allowances must be added. The 1 cm seam allowance allowed on the block is suitable for plain seams. Other seams usually require extra seam allowance; this must be added to the pattern. The extra width of seam allowance required will depend on the type of seam and the distance between seam and top stitching. Two examples are shown opposite.

For the mass production of lightweight garments, enclosed seams (e.g. collars, cuffs) have their seam allowance reduced to 0.5 cm.

INLAYS

Inlays are extra material allowed on some seams in case an alternation is necessary. They are always allowed on garments cut for individual customers (bespoke tailoring). Most manufacturers allow inlays on certain seams.

Working without Seam Allowances

If you wish to work without seam allowances during pattern adaptation, construct the blocks following the instructions, then cut off the seam allowances where marked. You will be able to follow the pattern procedures in the book, but you must ignore any instruction that tells you to add seam allowance, and ignore the shaded sections of seam allowance on the diagrams. When the pattern is completed the appropriate seam allowances can be added where required.

The construction of the kimono blocks (page 46 and 48), should be based on a block that includes seam allowance.

Points to note when Pattern Cutting

1.         When measuring curves use the tape measure on its edge.

2.         Accurate, clear lines are essential, and these can only be achieved

with the use of hard sharp pencils; sharpened with a pencil

sharpener, not a knife. Sketchy lines have no place in pattern

cutting.

3.         Notches are almost always marked at 90 degree to the seam line on which they are placed.

4.         The two sides of a dart must always be identical in length.

5.         Grain lines are marked parallel to the CF or CB except in a few cases, for instance a flared panel in a skirt would have the grain line marked through its centre as in a sleeve.

6.         Calico is available in varying weights and qualities, so whenever possible use the type most similar to the fabric chosen for your garment to test your pattern.

7.         If the pattern is to be used on a fabric with a nap,  i.e. corduroy, mark grain line in normal position but have the ‘arrows’ facing in one direction-  usually upwards.

Seam Allowance Guide