Good fabrication begins with measurements that describe the finished treatment, not just the window opening.
Start With the Installation Condition
Before taking finished treatment dimensions, establish what the treatment is mounting to and how it is expected to operate. A drapery panel hanging from a decorative rod can require different information than a functional treatment on a traversing track.
Confirm the opening, wall conditions, trim, floor, hardware location and any nearby obstacles that may affect returns or stack space.
Measuring Width
Separate the window opening from the finished treatment width. The finished width of a functional treatment is normally driven by the hardware or track coverage rather than the glass alone.
- Measure the intended hardware or track span.
- Identify whether the treatment is split draw, one-way draw or stationary.
- Record return dimensions where the treatment comes back toward the wall.
- Record center overlap if the hardware or design requires it.
Stationary panels should still be specified with an intended visual width rather than simply described as “decorative.” The workroom needs to know how much finished face width the panel should occupy.
Measuring Finished Length
Measure from the actual treatment hanging point to the intended bottom of the drapery. The hanging point changes with the heading and hardware, so do not assume every treatment begins at the top of the rod.
Decide whether the finished look should clear the floor, just meet it, break slightly, or intentionally puddle. For most precise installations, take multiple floor measurements because finished floors and ceilings are not always perfectly level.
Returns, Overlap and Stack Space
Returns and overlap can materially affect both finished dimensions and fabric requirements. Stack space matters when a functional treatment needs to clear as much glass as possible when open.
When these conditions are unusual, include a photograph, sketch or hardware reference with the project information rather than trying to communicate the entire condition in one number.
A Practical Field Checklist
- Window or opening width and height
- Hardware or proposed hardware span
- Finished treatment width
- Finished treatment length
- Return dimensions
- Overlap where applicable
- Draw direction
- Floor variation
- Obstructions such as radiators, furniture, trim or built-ins
- Photos of the installation condition