How to measure
10 minutes and a tape measure
Before you start: you're measuring the brick opening (the structural hole in the wall), not your old window frame. We make the window to fit the opening.
Then we take over. Every order — every single one — comes back to you as a production drawing showing each window with its final dimensions.
Nothing is manufactured until you've approved your drawings. And if you'd rather not measure at all, book a measuring visit (£249) and we'll guarantee the fit.
Width
Measure the brick-to-brick width at the top, middle and bottom of the opening, in millimetres. Write down all three. We use the smallest.
Height
Measure sill to lintel at the left, centre and right. Again, three numbers, and we use the smallest.
Check the diagonals
Measure corner to corner both ways. If they differ by more than 10mm, tell us in the order notes — openings are rarely perfectly square, and we allow for it.
Repeat for every opening — no copying
Two windows that look identical are often 10–20mm different. Measure both. (If two openings genuinely must match, tell us which.)
Wide openings
If an opening is wider than about 1600mm, it'll usually be made as two sashes in one frame with a timber divider between them. Just give us the full opening size — never split it into window sizes yourself; the divider width is where DIY arithmetic goes wrong, and we've seen it happen.
Old frame staying or going?
Tell us whether the existing frame comes out completely (usual) or you're fitting within it. It changes what we make.
Worried about getting it wrong? Read our re-makes promise — mismeasures don't cost full price twice.