Question 1

What size hinges do I need for a standard door?

Accepted Answer

For a standard internal door (35 mm thick, up to 40 kg), use 75 mm (3 inch) butt hinges — two hinges for doors up to 2040 mm tall. For heavier doors or doors over 2040 mm, use 100 mm (4 inch) hinges and fit three hinges. External doors typically need 100 mm hinges with three per door as standard due to their greater weight.

Question 2

How many hinges does a fire door need?

Accepted Answer

Fire doors (FD30 and FD60) must have a minimum of three hinges. These must be CE-marked steel butt hinges — brass hinges are not acceptable on fire doors. The hinges must be 100 mm (4 inch) and at least grade 11 to BS EN 1935. The top hinge should be 150 mm from the top, the bottom hinge 225 mm from the bottom, and the middle hinge centred between them.

Question 3

What are parliament hinges used for?

Accepted Answer

Parliament hinges have wide leaves that project beyond the door frame, allowing the door to fold back 180° flat against the wall. This is essential where doors open against a return wall or into a corridor. Common sizes are 100 mm and 150 mm. They are also used on shutters and where maximum clear opening width is needed.

Question 4

What is a rising butt hinge?

Accepted Answer

Rising butt hinges lift the door as it opens by approximately 10 mm, allowing it to clear thick carpets or uneven floors. They are handed (left or right) and are self-closing — the door will swing shut under its own weight. They come in 75 mm and 100 mm sizes and are available in steel, brass and chrome finishes.

Hinge Size (mm)	Imperial	Door Thickness	Max Door Weight	Number Required
50	2"	Up to 25 mm	Up to 10 kg	2 (cupboard doors)
63	2.5"	Up to 30 mm	Up to 20 kg	2 (lightweight doors)
75	3"	35 mm	Up to 40 kg	2 (standard internal)
100	4"	44–54 mm	Up to 80 kg	3 (external, fire doors)
125	5"	54+ mm	Up to 120 kg	3 (heavy external)

Requirement	Specification
Minimum number	3 hinges
Minimum size	100 mm (4 inch)
Material	Steel only (not brass or aluminium)
Grade	Min. Grade 11 to BS EN 1935
Certification	CE marked
Intumescent pads	Required behind each hinge
Top hinge position	150 mm from top of door

Position	Standard Door	Fire Door
Top hinge	150 mm from top	150 mm from top
Bottom hinge	225 mm from bottom	225 mm from bottom
Middle hinge	Centred (if fitted)	Centred (mandatory)

Size (mm)	Projection (mm)	Typical Use
100 x 100 x 4	~50	Internal doors against return walls
150 x 100 x 4	~75	External doors, deep architraves

UK Hinge Sizes — Door Hinges Guide

Standard Butt Hinge Sizes

Fire Door Hinge Requirements

Hinge Positioning

Parliament Hinge Sizes

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