Accurate measuring and cutting is required when planning the fitting of a new door.
The sizes you need to take are those for the overall width, not just the existing door sizes. The reason for this is because the PVC door is always supplied with its own frame.
Always measure the top, middle and bottom widths from the inside and check the height. Repeat the process for the outside sizes. In most cases if the door/frame being replaced is timber it is better to remove the existing timber frame so as to keep the opening sizes as large as is possible but please remember that most PVC frames/doors are made to a maximum size of 940mm overall.
ALWAYS GIVE YOUR MANUFACTURER THE TIGHT/OVERALL SIZES LESS a total of 6mm IN HEIGHT AND WIDTH.
When fitting the new door you will need to "TOE & HEAL" the frame. This means that after getting it level on the top, side and face with a spirit level you may need to alter the hinges on the vertical or lateral planes. Normally the hinges have a "cam" or an offset centre sleeve which pulls the door in, out or across. Adjust as required, no matter what the spirit level tells you!
Any questions, email firstname.lastname@example.org
Info supplied by www.DirectDoors.com