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For optimal fit and installation, we strongly recommend consulting a qualified fitter to determine the precise dimensions required for your project. Accurate measurements are essential to ensure proper installation and functionality.

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General Guidance

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• Measure the opening from brick to brick for both height and width at multiple points to verify straightness.

• In the event of variations, always use the smallest measurement.

• Deduct approximately 10mm from each measurement (5mm allowance on each side) to accommodate fitting tolerances.

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Measuring Procedure

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• Always take measurements from the exterior of the property.

• Measure the opening in three locations for both width and height.

• Use the smallest measurement obtained and deduct approximately 10-15mm for fitting allowance.

• All measurements should be recorded in millimetres (mm).

• Height measurements should be taken from the underside of any existing removable cill, unless a cill is not required.

• For rendered properties, remove sufficient render to measure to the brickwork edge.

• Do not rely on dimensions of existing frames, which may have warped over time.

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Important: The total height measurement will include a 25mm high drainage cill, unless no cill is required.