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Single-Storey Frames, Shells and Lightweight Coverings 243
corner posts, aluminium patent glazing to the pitched roof and an aluminium ridge section.
The lantern light is bolted to an upstand curb (in common with all rooflights fixed in a flat
roof) to resist wind uplift, and the roof covering is dressed to a height of at least 150 mm
above the surface of the flat roof.
Decklights are constructed as a hipped or gable-ended glazed roof with no upstand sides;
thus they provide daylight to the space below but no ventilation, as shown in Figure 4.79
and Figure 4.80. This deck light is constructed with lead sheathed steel glazing bars pitched
and fixed to a ridge and bolted to a steel tee fixed to the upstand curb.
A variety of shapes are produced to serve as rooflights for flat roofs, as illustrated in
Figure 4.81. The advantage of the square and rectangular shapes over the circular and ovoid
ones is that they require straightforward trimming of the roof structure around the openings
and upstands. Plastic rooflights are made as either single skin lights or as sealed double
skin lights, which improves their resistance to the transfer of heat. Plastic rooflights are
bolted or screwed to upstand curbs to resist wind uplift, and the roof covering dressed
against the upstand as illustrated in Figure 4.82. To provide diffused daylight through
Hipped end
Curb
Patent
glazing
Figure 4.79 Deck light (3D view).
Steel ridge
Lead flashing
Lead sheathed steel
glazing bars
6 wired glass
60
Ends
hipped
Glazing
bars
Glazing bar
cleat
Fixing plate
ragbolted to
concrete curb
Curb and
skirting of
roof covering
Tee
Glass
stop
Concrete curb
100 wide, 150 high
Figure 4.80 Deck light.