Width & Height

The width and height of the aperture should be measured at three points: top, middle & bottom.

The smallest dimension should be used to determine the measurement.

See illustration

Diagonal measurement

If the diagonals are more than 10mm different, please let us know.

Cill Extensions

The distance from the face of the building to the front face of the cill extension should be no less than 25mm.

See illustration

Casement

Learn about measurements required for a range of bay windows. Note: All measurements we need are related to the inside face of the window frame.

See illustration

Typical Edge Connections

See illustration for examples of typical edge conditions.