How to Write Construction Notes for Fashion Tech Packs
Learn how to write clear garment construction notes — seam types, stitch specifications, assembly sequence, and finishing details that manufacturers need.
What construction notes communicate
Construction notes tell your manufacturer how to assemble the garment — not just what the garment looks like, but how it is built. They specify seam types, stitch counts, assembly order, and finishing treatments for every join in the garment.
Clear construction notes prevent the most expensive category of production errors: structural mistakes. Wrong seam types, missing topstitching, incorrect assembly sequence, and wrong stitch tension are all errors that require complete re-sewing of affected garments.
Seam type specifications
Every seam in a garment should have a specified seam type. Common seam types in fashion production include:
- SSa (superimposed seam): standard seam, two layers stitched together — most basic construction
- LSa (lapped seam): one layer overlaps the other — common for flat-felled denim seams
- BSa (bound seam): raw edge enclosed in binding — used for unlined jackets
- FSa (flat seam): butted edges joined by cover thread — used for activewear and underwear
- EFa (edge finish): single-layer edge treatment — hems, facings
Stitch specifications
Each seam type needs a stitch specification: stitch type (lockstitch, chainstitch, coverstitch), stitches per inch (SPI), needle count, and thread type.
Standard specifications: lockstitch 301 at 10-12 SPI for most woven construction, chainstitch 401 for knit side seams, coverstitch 406 for knit hems. Topstitching is typically 8-10 SPI with heavier thread.
Assembly sequence
Construction notes should include assembly sequence — the order in which garment components are joined. This prevents inefficient construction and ensures that seam intersections are clean.
A typical t-shirt assembly sequence: (1) shoulder seams, (2) attach neck rib, (3) set sleeves, (4) close side and underarm seams in one pass, (5) hem sleeves, (6) hem body. Changing this sequence affects seam quality and production efficiency.
How AI generates construction notes
AI tech pack generators produce construction notes appropriate to the garment type and fabric weight. A heavyweight hoodie gets reinforced seam specifications while a lightweight blouse gets finer stitch counts.
The AI specifies seam allowances, stitch types, and topstitch details for each construction point. Structural elements like pockets, closures, and collars get dedicated construction callouts with specific assembly instructions.
Common construction note errors
The most common error is specifying the wrong stitch type for the fabric — lockstitch on stretch knits causes seam cracking, while chainstitch on stable wovens wastes production time. Another common error is missing bartack specifications at stress points (pocket corners, fly base, belt loop tops).
AI-generated construction notes avoid these errors by matching stitch type to fabric properties and including stress-point reinforcement specifications automatically.