Flat Roofs ~ these roofs are very seldom flat with a pitch of 0°
but are considered to be flat if the pitch does not exceed 10°. The
actual pitch chosen can be governed by the roof covering selected
and/or by the required rate of rainwater discharge off the roof. As
a general rule the minimum pitch for smooth surfaces such as
asphalt should be 1 : 80 or 0°†43^0 and for sheet coverings with laps
1 : 60 or 0°†57^0.
Methods of Obtaining Falls ~
Wherever possible joists should span the shortest distance of the
roof plan.
Timber Flat Roofs up to 4m Span