Guides for measuring your door opening when replacing with a PVC or Composite Door

(Please select the guide appropriate for you)
(Always measure door & frame combined)
(A new or 2nd hand door can not be fitted to an existing frame)

Guide A: Replacing an existing door. (i.e. Door screwed & plastered into place)

Width (measured in millimetres)
The width should be measured at three locations; top, middle and bottom, on the inside & the outside. The largest of these measurements plus 14mm (7mm plaster cover each side) should be taken as the width.

Height (measured in millimetres)
The height should be measured at three locations; left, middle and right, on the inside & the outside. The largest of these measurements plus 7mm (7mm plaster cover at the top) is taken as the height.

Note: If you have a wooden or tiled floor Guide A will work perfectly with a regular PVC door threshold (bottom of frame). If you need an aluminium low threshold door (e.g. wheelchair access) care should be taken that the door leaf will have enough clearance to open in. (i.e. you don’t want the bottom of the door rubbing off your timber floor.)
In the case of low thresholds also measure from the top of your timber floor to the top of the door frame plus 7mm and note this separately. Call it the maximum floor clearance height.

Guide B: For new houses or extensions where the blocks are not plastered yet. (i.e. No plastered reveals)

Width (measured in millimetres)
The width should be measured at three locations; top, middle and bottom. The smallest of these measurements minus 5mm should be taken as the width.

Height (measured in millimetres)
The height from the floor to the lintel should be measured at three locations; left, middle and right. The smallest of these measurements minus 5mm is taken as the height.