Definition of ceiling
Approved document B, Fire Safety, Volume 1 Dwelling houses, defines a ceiling as:
A part of a building which encloses and is exposed overhead in a room, protected shaft or circulation space. (The soffit of a rooflight is included as part of the surface of the ceiling, but not the frame. An upstand below a rooflight would be considered as a wall.)
For the purposes of the performance of ceiling linings, a ceiling includes:
- the surface of glazing;
- any part of a wall which slopes at an angle of 70º or less to the horizontal;
- the underside of a gallery; and
- the underside of a roof exposed to the room below.
But a ceiling does not include:
- trap doors and their frames;
- the frames of windows or rooflights and frames in which glazing is fitted; or
- architraves, cover moulds, picture rails, exposed beams and similar narrow members.
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