LOW ROOF PITCHES

Unless there is adequate positive fall in a roof, there is
danger of ponding, which can lead to a reduced service life,
particularly in coastal areas.
At low slopes, say around 1 in 50 (1°) slope, all roof supports
must be in the one plane because slight variations can
result in zero or negative fall. This may occur even after
completion of the building as the result of settlement,
timber warping or shrinking, or extra loadings (like air
conditioners).
Minimum recommended roof slopes are listed in Table
2.12.1 of the LYSAGHT Roofing and Walling Installation
Manual. As a guide, wherever possible, you should design
for a minimum slope of 1 in 30 (2°). Roof slopes lower than
the recommended minimum may be available subject to
enquiry and will be dependent upon the roof application
and building details.