Sprockets may be provided at the eaves to reduce the slope of a
pitched roof. Sprockets are generally most suitable for use on wide
steeply pitched roofs to:
- enhance the roof profile by creating a feature.
- to slow the velocity of rainwater running off the roof and
prevent it over-shooting the gutter.
Where the rafters overhang the external wall, taper cut timber
sprockets can be attached to the top of the rafters. Alternatively,
the ends of rafters can be birds-mouthed onto the wall plate and
short lengths of timber the same size as the rafters secured to the
rafter feet. In reducing the pitch angle, albeit for only a short
distance, it should not be less than the minimum angle
recommended for specific roof coverings.
Types of sprocketed eaves
rafter
rafter
ceiling joist
ceiling joist
rafter end
birds-mouthed
onto wallplate
wallplate
sprocket to
top of rafter
sprocket to
side of
rafter
Sprocket Roof