How to measure for curtains on site: a survey method for design and build teams

Measure once the ceiling pocket is boarded and finished, the track or pole position is fixed and the finished floor level is known. Curtains should not be ordered from drawings alone.

Drawings show intent, but built gypsum pockets, concrete soffits and floor build-ups usually differ from the drawings by a few centimetres. For floor-length curtains, a 1–2 cm error is enough to leave a curtain hovering or bunching.

A practical design and build sequence has two surveys:

• Initial survey: after pockets are built, to fix quantities and order fabric. The matching take-off is covered in writing BOQ lines for curtains.
• Check measure: after flooring and skirting are installed, before drops are cut. This survey fixes the finished length.

If the programme forces making before flooring, record the intended finished floor level and build-up thickness on the survey sheet.

Bring floor plans with window references, a curtain schedule stating intended products, and the right tools.

• Laser measure for drops and pocket lengths; steel tape for pocket width and height, small distances and cross-checks.
• Plans and pocket sections with a consistent window code (for example L12-BR1-W01: level, room, window).
• Curtain schedule: heading, layers (main and sheer), motorised or manual, draw direction. The heading changes how drop is calculated, see curtain tracks and ceiling pockets.
• Survey sheet on paper or tablet, plus a phone for photos of every window. When the project is set up on SEAMATER, use the same window codes in the survey and the quote request so figures match line by line. SEAMATER can survey and measure on the project's behalf; the method below is for specifiers who want to measure or check figures themselves, in Vietnam or on overseas projects.

For curtains in a pocket, measure the internal pocket length wall to wall at the track line. For wall or ceiling fixing without a pocket, measure the intended track or pole length, not the window opening.

1. Measure pocket length at the front and back of the pocket; record both if they differ, as gypsum walls are not always parallel.
2. Where a pocket runs across several windows, record the overall length and the position of columns or mullions.
3. For wall-fixed tracks or poles, allow typically about 15–20 cm beyond the frame on each side, more where the stackback is large, so the stacked curtain clears the glass. Record the actual wall space available, as columns, partitions or built-in joinery may limit it.
4. Record draw direction: pair opening to both sides, or single panel to left or right as seen from inside the room.

Do not apply fitting deductions on site. Record raw dimensions; the supplier deducts according to the track, end brackets and motor.

Measure from the underside of the pocket (or the track or pole position) to the finished floor at three points: left, centre and right. The supplier uses the lowest reading for the finished length of floor-length curtains.

Concrete soffits and floors are rarely perfectly level; differences above 1 cm between readings should be flagged so the team can agree how to handle them. Finished length depends on heading: wave and pinch pleat measure from the track, eyelet from the top of the pole, tab top adds the pole diameter. That is why surveyors record raw figures and let the supplier convert them.

Agree the hem clearance with the client before making:

In humid tropical climates, curtains touching the floor absorb moisture at the hem; 1–1.5 cm clearance is the safer default.

Record anything that could block the track run or catch the curtain, with photos showing a tape for scale.

• Air-conditioning units, diffusers, sprinkler heads and smoke detectors near or inside the pocket.
• Handles, hinges and swing of doors and casement windows; for aluminium sliding doors, check the gap between track and frame so curtains do not rub.
• Sockets, switches and control panels on the wall behind the curtain.
• Power point position for motorised curtains.
• Pocket internal width (glass to pocket edge) and height, to confirm room for one track (typically about 15–20 cm) or two tracks (about 25–30 cm).
• Adjacent wall material (concrete, brick, gypsum), which sets the fixing method.

Power and pocket readiness checks for installation are in curtain installation: site readiness and handover.

A standard sheet keeps measurements from different surveyors readable in the same way. One row per window.

The sheet also feeds fabric take-off; see how to calculate curtain fabric quantity.

Most errors come from surveying at the wrong time, deducting on site and recording figures without a window reference. Three rules prevent most of them:

1. Record raw, never converted. No site deductions; centimetres with one decimal.
2. Every figure has a window reference and photos. One overall shot, close-ups of both pocket ends and the floor junction.
3. Two people read every figure. One measures, one records and reads back; repeat units are still measured individually, because pockets in identical apartments can differ.

SEAMATER surveys and measures for curtains and wallpaper, and checks fabric quantities for the customer, so raw figures, deductions and installation stay consistent between the person measuring and the person fitting. Unusual readings should be caught before fabric is cut.