Bay Windows

E1/AS1 does not prescribe a need for a building to have spouting, it merely requires that concentrations of water gathered by structures does not enter the building or cause damage or nuisance to other property. This is traditionally achieved by using gutters and downpipes to discharge roof catchments into stormwater drains.

Minor wall projections such as bay windows and boxed penetrations are treated as part of the wall catchment and are typically excused from requiring spouting and downpipe, provided the plan view surface area of individual projections does not exceed 5 m2.