This composite door measuring guide is only a guide to help an experienced tradesperson or competent DIYer carry out a survey. We do not accept any liability for inaccurate surveys.
If you do not feel confident enough to install your new composite door, we do offer an installation service to most parts of the UK. Please contact us to find out if we cover your area.
You are measuring the overall width and height of the door including the door, the frame and cill.
Width: Measure in 3 points; top, middle and bottom and take the smallest measurement and deduct 10mm.
Height: Measure again in 3 points; left, centre and right and take the smallest measurement and deduct 10mm.
Diagonals: Ensure the opening is square by measuring the diagonals as shown in yellow. There should be no more than 5mm difference between each measurement.
Overall measurements are to the outer edges of the frame.
When entering sizes for manufacture they include the cill which is 30mm high if required.