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Composite Door Measuring Guide

This section 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 email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it   to find out if we cover your area.

Download Measuring Guide


door measuring guide You are measuring the overall width and height of the door including the door, the frame and cill.


Measure in 3 points; top, middle and bottom and take the smallest measurement and deduct 10mm.

Measure again in 3 points; left, centre and right and take the smallest measurement and deduct 10mm.

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

outer measurement

When entering sizes for manufacture they include the cill which is 30mm high if required

 Composite door outer frame measurements


When measuring your existing door aperture check the inside measurements against the outside measurements to check the frame will clear the inside plaster line as shown below.

 Surveying measurements


If the plaster line or internal wall sits to far in, it will be necessary to use the appropriate addon as shown below.

plaster line 

However, you may have a box sash scenario when the reverse of the above is shown below. You will need to measure brick to brick externally then add 5-10mm each side so the outer frame sits nicely behind the existing brickwork.

Surveying measurements 

With a box sash installation the frame can be fixed as follows:
(It will be necessary to remove existing architrave to survey accurately.)

plaster line 


Cill options shown below and typical applications.
Standard cill height is 30mm if required.

Door cill options 

Manufacturing parameters

 manufacturing sizes(not including 15mm add on)

We recommend these composite doors are installed by a competent tradesperson with assistance, as these door are heavy.



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