Six Hotel Windows, a Half-Drop Repeat and Two Bad Shortcuts
A boutique soft-furnishing studio in Udaipur has won a contract for six identical drawing-room windows in a heritage hotel. Each finished curtain panel must cover 1.50 m of width and hang 2.30 m from a 3.00 m rail; the client wants 2.5× fullness, a 15 cm bottom hem and a 10 cm heading allowance. The chosen fabric is a 54-inch-wide (1.37 m) cotton-linen print with a 32 cm vertical repeat on a half-drop, 4% shrinkage in length after the first wash, and a slight bow in the weft. The mill sells only full 30 m bolts. The interior designer wants washable, unlined curtains on a slim 19 mm rod with an eyelet (grommet) heading, installed in 12 days. The cutter proposes two panels per window to 'save fabric' and suggests skipping pre-washing to save time.
1. Calculate the fabric to buy. Show the panel count per window, the cut length including repeat and shrinkage rounding, the half-drop allowance and wastage.
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Panel count per window
- Required flat width = 1.50 m × 2.5 fullness = 3.75 m.
- Usable fabric width after trimming the selvedge, say 1.35 m.
- 3.75 ÷ 1.35 = 2.78 → 3 widths per window.
- Six windows → 18 panels.
Cut length per panel
- Finished drop 2.30 + 0.15 hem + 0.10 heading = 2.55 m.
- Add 4% length shrinkage: 2.55 × 1.04 = 2.652 m.
- Round up to whole repeats: 2.652 ÷ 0.32 = 8.29 → 9 repeats = 2.88 m.
Half-drop allowance
- On a half-drop repeat, alternate panels must start half a repeat lower so the motif continues across the join: 0.32 ÷ 2 = 0.16 m extra on 9 of the 18 panels.
- 9 × 2.88 = 25.92 m; 9 × 3.04 = 27.36 m; total = 53.28 m.
Wastage
- Add about 5% for squaring the bowed weft, cutting round the selvedge and matching at joins: 53.28 × 1.05 ≈ 55.9 m.
- Only 30 m bolts are sold: two bolts = 60 m, leaving roughly 4 m spare. That spare is useful on an installation with a bowed weft - do not cut into it early.
Check: if the weft bow runs through the whole bolt, add one repeat per panel until the bow is cut out; ask the mill for the bow figure before confirming the final quantity.
2. Judge the cutter's two proposals - two panels per window, and no pre-washing - with numbers.
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Proposal 1 - two panels per window: reject.
- Two panels give 2 × 1.35 = 2.70 m of flat width against a 3.75 m requirement, i.e. 1.8× fullness instead of 2.5×. The curtains will hang almost flat, the print will read as a stretched sheet of fabric rather than drapery, and 3.75 m of fabric pushed onto a 3.00 m rail will barely fold.
- The saving is only one width per window (6 panels ≈ 17 m), but the client specified 2.5× in the contract. A visible shortfall across six windows in a hotel lobby is a remake, not a compromise.
- With a 32 cm repeat there is a second loss: narrower panels mean more joins per window, and every join consumes half a repeat. The apparent saving shrinks further.
Proposal 2 - skip pre-washing: reject.
- At 4% length shrinkage on a 2.30 m drop, the curtain shortens about 9.2 cm after the first wash. A hem is normally set 1–2 cm off the floor; after washing it would sit 7–8 cm off the floor, visibly and permanently.
- We have already built 4% into the cut length, so the shrinkage is financially covered - but the evenness is not. Cotton-linen shrinks unevenly across the width, the joins move, and the client washes hotel curtains.
- The correct response to the 12-day deadline is to pre-wash and dry the 60 m in the first three days, or to cut the shrinkage allowance as above and state it in writing to the designer, with a weighted hem to hold the drop.
Recommendation: keep 3 widths per window, pre-shrink or document the allowance, and get the designer's written sign-off on the fullness and the drop tolerance before cutting.
3. The designer insists on an unlined eyelet heading on a 19 mm rod for this cotton-linen. Assess the specification and state what you would change or confirm in writing.
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Will it work? Partly, with conditions.
- Grommet versus rod: a 19 mm rod needs a grommet with an internal diameter of at least 30–40 mm so the curtain runs without binding. Confirm the grommet size before ordering; a 40 mm barrel grommet is the normal pairing for a 19 mm rod.
- Grommet spacing: at roughly 15 cm centres, a 3.75 m panel needs about 25 grommets - an even number with the two end gaps equal, or the heading twists. Spacing must be calculated per panel, not assumed.
- Unlined cotton-linen on eyelet: eyelet headings sit high and show the back of the fabric, and an unlined 240 gsm cotton-linen in a 2.5× fullness will hold folds but may look thin against a bright window. Recommend either a lined heading or a fusible/wool-facing stiffener in the 10 cm heading so the top edge stands and the eyelets do not pull out.
- Weight: three widths hanging from grommets exert real load on the heading. Reinforce the heading with interfacing and use a lock-stitch or bar-tack at each grommet position.
- Washability: confirm the grommets are rust-proof and that shrinkage has been pre-treated, since the client will wash them.
- Put it in writing: issue a short specification sheet - rod diameter, grommet inner diameter and spacing, heading depth with stiffener, finished drop and tolerance, and the shrinkage allowance. Ask the designer to sign it before the fabric is cut.