- All measurements to be taken from external openings
- When measuring always measure in millimetres
- Measure the width of the opening in 3 places:
- Bottom of opening left to right
- Middle of opening left to right
- Top of opening left to right
- Measure the height of the opening in 3 places:
- Left of opening top to bottom
- Middle of opening top to bottom
- Right of opening top to bottom
Take the smallest measurement for the width and the smallest for the height and take off 10mm off each of them e.g.
Window opening = 1800mm width x 1000mm height
Deduct 10mm from the width and height = 1790mm width x 990mm height
The above dimensions will be the manufacturing/order sizes that you will need to input when ordering windows and doors from our website.
You deduct 10mm from the width and height to allow for tolerance when fitting.