Measure the opening, not the old window: the width at the top, middle and bottom, and the height at the left, middle and right, in millimetres. Use the smallest of each. Send those sizes with the wall type, reveal depth and which way each window opens. We set the manufacturing deductions on the shop drawings, and you sign them before anything is made.
Step by step
- Width: three measurements, top, middle and bottom, from frame stud to frame stud (or brick to brick on double brick). Write down the smallest.
- Height: three measurements, left, middle and right, from the sill to the head. Write down the smallest.
- Wall type: brick veneer, weatherboard or cladding, double brick, or blockwork. It changes the frame fixing and reveal.
- Reveal depth: the wall thickness the frame sits in, so the reveals and sub-sills come out right.
- Opening direction: which side slides or hinges, viewed from outside.
- Photos: one of each opening from outside and inside, with a tape measure in shot.
New builds and extensions
Send the window schedule from your plans or the architectural drawings. If the frame is not up yet, sizes come from the plans and we confirm them on the shop drawings. Check them against the frame on site before you sign.
Renovations
For replacement windows, take the old window out of one opening first if you can, so you are measuring the real structural opening. Older houses are rarely square; measure the diagonals too and tell us if they differ by more than about 10 mm.
Write it as a schedule
| Label | Type | Width × height (mm) | Glass | Notes |
|---|---|---|---|---|
| W01 Bed 1 | Awning | 1210 × 1030 | Double glazed clear | Brick veneer, flyscreen |
| D01 Living | Stacker, 3 panels | 3610 × 2100 | Double glazed low-E | Opens to deck, left fixed |
| W05 Bath | Awning | 610 × 1030 | Double glazed obscure | Toughened |
The quote builder does this for you: add each window, see it drawn to scale, and send the list.
Questions
Do I measure the window or the opening?
The opening. Measure the structural opening the new frame will sit in, not the old window frame.
Which measurement do I use?
The smallest of the three widths and the smallest of the three heights.
Should I allow a gap?
Send the actual opening sizes. We set the manufacturing deductions and show the final frame sizes on the shop drawings for you to check.
What is a reveal?
The lining that covers the wall thickness between the window frame and the inside wall. Its depth depends on your wall type.
Can I send plans instead of measuring?
Yes, for new builds. We price from the window schedule on the plans and you confirm sizes on site before signing the shop drawings.