Mobiltech
A 2.95 m curtain from 2.5 m fabric takes two widths welded together, and the second width is mostly trimmed away.
— m²
Whole roll widths over the cut length, for every curtain
Each curtain is one piece running the length of the body, wrapped round the end poles, with the top fixing allowance and a bottom hem for the strap pockets. When the cut height is more than one roll width, widths are welded along the length, and the trimmed edge of the last width is bought but not used. Dimensions, allowances, fabric and strap spacing are yours or the body builder's. Mass is the fabric in the curtains; straps, buckles, rollers and weld overlaps are extra. **Curtains are not load restraint unless the body is certified for it; secure the load as the body's rating and the load securing rules require.**
Curtain-Sided Trailer Curtains: Cut Size, Fabric Widths, Fabric Bought, Mass & Straps — free, with the formula and a worked example, at Textile School.