Civil Engineering Reference
In-Depth Information
Lintels
Lintels are the timbers that span the top of windows, doors and other openings in the wall.
Their specification depends on the size of span across the opening and whether they are
also supporting a floor joist, and thus how much load they are taking.
In its most simple form - over doors or windows that are not supporting upper floor loads
- the lintel may simply be part of the framework for the door or window, and consist only
of a doubled-up timber to form a stable fix for its frame. When it is taking a load, a larger-
section timber may be specified to form a 'structural lintel' as part of the structural frame.
For very high loads, an engineered timber lintel might be used.
Window framework
The framework for windows is created by building a 'box' from two horizontal and two
vertical timbers. This is then fixed into the frame in such a way that any load taken by the
lintel is safely transferred down through the structural frame. Window frames do not ne-
cessarily sit perfectly between two vertical studs in the frame, and may need to be fixed to
the nearest studs with noggins (see right) at each side.
Larger windows may span several vertical studs in the frame, which means that these studs
need to be cut and re-fixed to both the lintel and the horizontal timber at the bottom of the
window.
Larger windows often require doubled timbers for the framework, as specified by the
frame designer based on the span of the opening and the structural load taken by the win-
dow frame.
Door framework
The framework for doors is created in the same way as for windows, although two vertical
timbers and a lintel are usually all that is required to define the opening, unless there is to
be a step up to the door.
If the door position doesn't fit exactly within existing vertical stud positions in the frame,
then the position of an existing stud or studs can be moved back towards the previous
stud(s) (i.e. decreasing the distance between them), and the repositioned stud can then form
the side of the door opening. If, however, moving the stud to the correct position would
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