- Take multiple width and height measurements rather than relying on a single point.
- Check whether the reveal is square, level and free from obstructions.
- Use the smallest tight measurement where appropriate.
- Allow a sensible fitting tolerance to suit the installation.
- Where existing bars need to line through, measure to the centre point of those bars.
As a general guide, many customers allow 6mm off both the width and height, giving an approximate
3mm gap around the product. This is guidance only and may need adjusting to suit the actual opening
and installation conditions.
