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Last edited 24 Jan 2021
Headroom in buildings and other structures
Between two floors, the headroom is the clear vertical space between the two decks, from the top of the finished floor level of the lower deck, to the underside of the soffit of the upper deck. Low headroom may increase the likelihood of injury or the difficulty of manoeuvring large objects.
The headroom may or may not be sufficient to allow people to pass under easily. If not sufficient, it will not be possible to pass through without crouching or striking the top surface.
On a flight of stairs, the headroom is the vertical distance between the pitch line (or nosing line) and the ceiling, taking into account any bulkheads. Approved Document K of the Building Regulations (section 1.11, diagram 1.3) stipulates a minimum headroom of 2m for all building types – whether on the stairs or on a landing.
Headroom may also refer to the clear, vertical height from a road’s top surface to the underside of a bridge or to the crown of a tunnel (or the ceiling of some buildings such as car parks). A sign indicating ‘low headroom’ warns that some vehicles may not be able to pass through without hitting the underside of the structure. In these cases, the clear height of the available headroom will be displayed, and there may be additional warning signs in advance of the low headroom or barriers to try to prevent impact.
Culvert, screen and outfall manual, (CIRIA C786) published by CIRIA in 2019, defines headroom as the: ‘Vertical gap between the water surface and the roof (soffit) of a culvert or outfall to allow for floating debris (also known as air draught).’
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