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close this bookCarpentry for Vocational Schools - A Teachers Handbook
close this folder20. DOORS
View the document(introduction...)
View the document20.1. Door frame
View the document20.2. Calculating of opening
View the document20.3. Fixing door jambs
View the document20.4. Hanging a door
View the document20.5. Types of doors

20.2. Calculating of opening

To calculate the width of the door opening , measure the width of the door, add two jambs thickness and 4 mm. To calculate the height of the opening, measure the height of the door, add head and 4 mm.

E.g. Width:


820 nun

Thickness of 2 jambs

+ 50 nun

+ 4 mm


Width of opening in the wall

= 874 mm



2040 mm

Thickness of one head

+ 25 mm

+ 4 mm


Height of opening in the wall

= 2069 mm

Door opening in the wall = 874 x 2069